Photochromic composition

ABSTRACT

A photochromic composition and a coating composition comprising a molecular compound of a chromene compound and an aromatic compound. The photochromic composition provides a photochromic optical material as a cured product and the coating composition is applied to a lens substrate and cured to provide a photochromic optical material. The above molecular compound is also provided.

FIELD OF THE INVENTION

[0001] The present invention relates to a photochromic composition whichcan contain a chromene compound having excellent photochromism in a highconcentration, a photochromic optical material, a process for producingthe same and a molecular compound used in the material and process. Morespecifically, it relates to a photochromic composition havingpolymerization curability which can be suitably used to form a coatingfilm having photochromism on the surface of an optical article such as aspectacle lens, or a photochromic composition which can provide anoptical article such as a photochromic spectacle lens or film by curinga polymer component by cooling or removing an organic solvent, aphotochromic optical material, a process for producing the same, and amolecular compound used in the material and the process.

DESCRIPTION OF THE PRIOR ART

[0002] Photochromism is a reversible phenomenon that a certain compoundchanges its color immediately upon exposure to light includingultraviolet rays and returns to its original color when it is placed inthe dark by stopping exposure. A compound having this property is called“photochromic compound” and various compounds have been synthesized sofar. Out of these photochromic compounds, chromene compounds haveexcellent durability and compounds which develop various colors such asyellow to light blue colors are known. Therefore, studies on thesecompounds are now being made aggressively.

[0003] For example, as a chromene compound having excellent physicalproperties, there are known a compound represented by the followingformula (A) which develops a yellow color and is disclosed in thepamphlet of WO98/45281 and a compound represented by the followingformula (B) which develops a blue color and is disclosed in the pamphletof WO96/14596.

[0004] These chromene compounds are generally used for various purposessuch as photochromic plastic lenses and coatings as a dispersion in apolymer matrix. As means of dispersing a chromene compound in a polymermatrix, there are known a method in which a thermosetting polymer matrixis impregnated with a chromene compound at a high temperature(WO96/14596) and a method in which a chromene compound is dissolved in apolymerizable monomer and then polymerized (WO97/48993).

[0005] However, in order to improve the photochromism of the abovechromene compound, various substituents are introduced into the chromenecompound, resulting in a great increase in its molecular weight.Therefore, the chromene compound does not diffuse in the polymer matrixsmoothly or its solubility in a monomer becomes low, thereby making itdifficult to disperse the chromene compound in the polymer matrix in ahigh concentration. For instance, when the chromene compound isdispersed by the above methods, the concentration of the chromenecompound which can be dispersed is about 0.5 wt % and it is extremelydifficult to disperse the chromene compound uniformly in a highconcentration of more than 1 wt %. Therefore, a polymer obtained bydispersing the chromene compound in accordance with the above methodshas a problem that the thickness of its coating film must be made largein order to obtain practical color development intensity. For example,when the polymer is used as a coating to form a thin film having athickness of 0.1 mm or less, satisfactory color development intensitycannot be obtained.

[0006] Thus, there is unknown a method of dispersing uniformly achromene compound having a polymer weight in a polymer matrix in a highconcentration with ease.

SUMMARY OF THE INVENTION

[0007] It is a first object of the present invention to provide aphotochromic composition which can dissolve a chromene compound in ahigh concentration.

[0008] It is a second object of the present invention to provide aphotochromic optical material which is a cured product of a uniformdispersion containing a chromene compound in a polymer matrix in a highconcentration.

[0009] It is a third object of the present invention to provide acurable composition which can easily and simply provide photochromism toan optical article by applying a curable composition as a coating agentwhich comprises the above chromene compound dissolved in a highconcentration to the surface of an optical article such as a plasticlens and a process for producing the same.

[0010] It is a fourth object of the present invention to provide amolecular compound of a chromene compound and an aromatic compound and aprocess for producing the same.

[0011] Other objects and advantages of the present invention will becomeapparent from the following description.

[0012] According to the present invention, firstly, the above objectsand advantages of the present invention are attained by a photochromiccomposition prepared by mixing together (1) 100 parts by weight of aradically polymerizable monomer or a polymer compound and (2) 0.01 to 20parts by weight of a molecular compound of a chromene compound and anaromatic compound.

[0013] According to the present invention, secondly, the above objectsand advantages of the present invention are attained by a coatingcomposition comprising:

[0014] (1) 100 parts by weight of a radically polymerizable monomer;

[0015] (2) 1 to 30 parts by weight of a molecular compound of a chromenecompound and an aromatic compound or a combination of this molecularcompound and a photochromic compound; and

[0016] (3) 0.01 to 10 parts by weight of a photopolymerizationinitiator, the number of parts by weight of the component being smallerthan the number of parts by weight of the above component (2).

[0017] According to the present invention, thirdly, the above objectsand advantages of the present invention are attained by a photochromicoptical material which is a cured product of the curable composition ofthe present invention.

[0018] According to the present invention, in the fourth place, theabove objects and advantages of the present invention are attained by aprocess for producing a photochromic optical material, comprising thestep of curing the curable composition of the present invention.

[0019] According to the present invention, in the fifth place, the aboveobjects and advantages of the present invention are attained by aphotochromic optical material which comprises a substrate and a curedcoating film of the above coating composition on at least one side ofthe substrate.

[0020] According to the present invention, in the sixth place, the aboveobjects and advantages of the present invention are attained by aprocess for producing a photochromic optical material, which comprises

[0021] applying the above coating composition to at least one side of asubstrate; and

[0022] curing the above coating composition by light or both light andheat.

[0023] Further, according to the present invention, in the seventhplace, the above objects and advantages of the present invention areattained by a novel molecular compound of a chromene compoundrepresented by the following formula (1) and an aromatic compound havinga molecular weight of 70 to 150, the molecular compound being used forpreparing composition of the present invention.

[0024] wherein R¹ and R² are each a substituted or non-substituted arylgroup, or a substituted or non-substituted aromatic heterocyclic group,and the divalent group represented by the following formula (2) is adivalent condensed polycyclic organic group which has a benzene ringcondensed to the 2H-pyran ring in the above formula (1) and may have asubsistent:

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a chart showing the proton nuclear magnetic resonancespectrum of a crystal (molecular compound) obtained in Example 1;

[0026]FIG. 2 is a chart showing the thermogram of a crystal (molecularcompound) obtained in Example 1; and

[0027]FIG. 3 is a chart showing the thermogram of a crystal obtained inComparative Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] The photochromic composition of the present invention is obtainedby mixing together a radically polymerizable monomer or a polymercompound (to be referred to as “solvent for a molecular compound”hereinafter) and a molecular compound of a chromene compound. When achromene compound is used in the form of a molecular compound, it can bedissolved easily in the above solvent for a molecular compound in a highconcentration. The photochromic composition of the present invention canbe cured by polymerization when the above solvent for a molecularcompound is a radically polymerizable composition, by cooling when theabove solvent for a molecular compound is, for example, a molten productof a polymer compound, or by removing a solvent for a polymer compound(also for the molecular compound) when the above solvent for a molecularcompound is, for example, a solution of the polymer compound. The thusobtained cured product can be used as an optical article such as aspectacle lens or film having photochromism itself or a coating film forproviding photochromism to various transparent substrates. The chromenecompound can be existent in a solution state relatively stably withoutseparating out from the obtained photochromic compound of the presentinvention. However, it is not confirmed whether the chromene compound isexistent in the form of a molecular compound. The inventors of thepresent invention assume that the chromene compound does not need to beexistent in the form of a molecular compound after dissolution and thatbonding power between the chromene compound and the aromatic compound isweakened in part or all of the molecular compound although the chromenecompound must be existent in the form of a molecular compound to promoteits solubility.

[0029] The radically polymerizable monomer used in the photochromiccomposition of the present invention is not particularly limited and anyknown compound having a radically polymerizable group such as(meth)acryloyl group, (meth)acryloyloxy group, vinyl group, allyl groupor styryl group may be used without any limitation. Out of these,compounds having a (meth) acryloyl group or (meth) acryloyloxy group asa radically polymerizable group are preferred from the viewpoint of easyacquisition and excellent curability.

[0030] In order to improve the chemical and mechanical properties suchas solvent resistance, hardness and heat resistance, and photochromismsuch as color development intensity and fading speed of the curedproduct obtained after curing, a radically polymerizable monomer havinga homopolymer L-scale Rockwell hardness of 60 or more (to be alsoreferred to as “high-hardness monomer” hereinafter) and a radicallypolymerizable monomer having a homopolymer L-scale Rockwell hardness of40 or less (to be also referred to as “low-hardness monomer”hereinafter) are preferably used in combination.

[0031] The L-scale Rockwell hardness is a hardness measured inaccordance with JIS-B7726. It can be simply judged whether the monomersatisfies the above requirement for hardness by measuring thehomopolymer of each monomer. Stated more specifically, as will be shownin Examples hereinafter, this can be easily confirmed by polymerizing amonomer to obtain a 2 mm-thick cured product, keeping it in a chambermaintained at 25° C. for 1 day and measuring its L-scale Rockwellhardness with a Rockwell hardness meter. In the polymer used to measurethe above L-scale Rockwell hardness, 90% or more of polymerizable groupsof the charged monomer must be polymerized. When 90% or more of thepolymerizable groups are polymerized, the measured L-scale Rockwellhardness of the cured product is generally an almost constant value.

[0032] The above radically polymerizable monomer having a homopolymerL-scale Rockwell hardness of 60 or more (high-hardness monomer) has theeffect of improving the solvent resistance, hardness and heat resistanceof a cured product after curing. To make this effect more effective, aradically polymerizable monomer having a homopolymer L-scale Rockwellhardness of 65 to 130 is preferred.

[0033] The high-hardness monomer is a compound having preferably 2 to15, more preferably 2 to 6 radically polymerizable groups in themolecule. Preferred examples of the high-hardness monomer includepolymerizable monomers represented by the following formulas (3) to (7).When there is a range in the number of repetitions which can be taken byrecurring units in the main chain in the polymerizable monomerrepresented by any one of these formulas, the polymerizable monomer maybe a mixture of a plurality of molecules having different numbers ofrepetitions.

[0034] In the above formula, R³ is a hydrogen atom or methyl group, R⁴is a hydrogen atom, methyl group or ethyl group, R⁵ is a tervalent tohexavalent organic residual group, f is an integer of 0 to 3, f′ is aninteger of 0 to 3, and g is an integer of 3 to 6.

[0035] In the above formula, R⁶ is a hydrogen atom or methyl group, B isa tervalent organic residual group, D is a divalent organic residualgroup, and h is an integer of 1 to 10.

[0036] In the above formula, R⁷ is a hydrogen atom or methyl group, R⁸is a hydrogen atom, methyl group, ethyl group or hydroxyl group, E is adivalent organic residual group containing a cyclic group, and i and jare each a positive integer or 0 which ensures that the average value of(i+j) is 0 to 6.

[0037] In the above formula, R⁹ is a hydrogen atom or methyl group, andF is an alkylene group having 2 to 9 carbon atoms in the main chainwhich may have a side chain.

[0038] In the above formula, R¹⁰ is a hydrogen atom, methyl group orethyl group, and k is an integer of 1 to 6.

[0039] R³, R⁶, R⁷ and R⁹ in the above formulas (3) to (6) are each ahydrogen atom or methyl group. The compounds represented by the formulas(3) to (6) have 2 to 6 (meth)acryloyloxy groups. When a plurality of(meth)acryloyloxy groups are existent in one molecule, they may differfrom one another but preferably are identical to one another from theviewpoint of easy acquisition (the same can be said of R¹³ and R¹⁴).

[0040] R⁴ in the above formula (3) is a hydrogen atom, methyl group orethyl group.

[0041] R⁵ in the formula (3) is a tervalent to hexavalent organicresidual group. The organic residue is not particularly limited and maycontain a bond other than a carbon-carbon bond, such as an ester bond,ether bond, amide bond, thioether bond, sulfonyl bond or urethane bondin the main chain. To obtain a homopolymer L-scale Rockwell hardness of60 or more, R⁵ is preferably an organic residual group having 1 to 30carbon atoms, more preferably an organic residual group having 1 to 15carbon atoms which may contain an ether bond and/or an urethane bond.

[0042] Further, f and f′ are each independently an integer of 0 to 3.When f are f′ are larger than 3, these monomers tend to have ahomopolymer L-scale Rockwell hardness of less than 60. To obtain anL-scale Rockwell hardness of 60 or more, the total of f and f′ ispreferably 0 to 3.

[0043] Illustrative examples of the high-hardness monomer represented bythe formula (3) include trimethylolpropane trimethacrylate,trimethylolpropane triacrylate, tetramethylolmethane trimethacrylate,tetramethylolmethane triacrylate, trimethylolpropane trimethacrylate,tetramethylolmethane tetramethacrylate, tetramethylolmethanetetraacrylate, trimethylolpropane triethylene glycol trimethacrylate,trimethylolpropane triethylene glycol triacrylate, ethoxylatedpentaerythritol tetraacrylate, ethoxylated pentaerythritoltetramethacrylate, pentaerythritol trimethacrylate, pentaerythritoltetramethacrylate, dipentaerythritol hexaacrylate, urethane oligomertetraacrylate, urethane oligomer hexamethacrylate, urethane oligomerhexaacrylate, polyester oligomer hexaacrylate, caprolactone modifieddipentaerythritol hexaacrylate and ditrimethylolpropane tetraacrylate.

[0044] B in the above formula (4) is a tervalent organic residual groupand D is a divalent organic residual group. B and D are not particularlylimited and may contain a bond other than a carbon-carbon bond, such asan ester bond, ether bond, amide bond, thioether bond, sulfonyl bond orurethane bond in the main chains thereof. To obtain a homopolymerL-scale Rockwell hardness of 60 or more, B is preferably an organicresidual group derived from a linear or branched hydrocarbon having 3 to10 carbon atoms, and D is preferably an organic residual group derivedfrom a linear or branched aliphatic hydrocarbon having 1 to 10 carbonatoms or an aromatic hydrocarbon having 6 to 10 carbon atoms.

[0045] To obtain a homopolymer L-scale Rockwell hardness of 60 or more,h is an integer of 1 to 10, preferably 1 to 6.

[0046] Illustrative examples of the high-hardness monomer represented bythe formula (4) include a tetrafunctional polyester oligomer having amolecular weight of 2,500 to 3,500 (EB80 of Daicel UCB Co., Ltd., etc.),tetrafunctional polyesteroligomer having a molecular weight of 6,000 to8,000 (EB450 of Daicel UCB Co., Ltd., etc.), hexagonal polyesteroligomer having a molecular weight of 45,000 to 55,000 (EB1830 of DaicelUCB Co., Ltd., etc.) and tetrafunctional polyester oligomer having amolecular weight of 10,000 (GX8488B of Dai-ichi Kogyo Seiyaku, Co.,Ltd., etc.).

[0047] R⁸ in the above formula (5) is a hydrogen atom, methyl group,ethyl group or hydroxyl group.

[0048] E in the above formula (5) is a divalent organic residual grouphaving a cyclic group. The organic residual group is not particularlylimited if it contains a cyclic group and may contain a bond other thana carbon-carbon bond, such as an ester bond, ether bond, amide bond,thioether bond, sulfonyl bond or urethane bond in the main chain. Thecyclic group contained in E is a benzene ring, cyclohexane ring,adamantane ring or cyclic group shown below.

[0049] The cyclic group contained in E is preferably a benzene ring andE is more preferably a group represented by the following formula:

[0050] wherein G is an oxygen atom, sulfur atom, or a group selectedfrom the group consisting of —S(O₂)—, —C(O)—, —CH₂—, —CH═CH—, —C(CH₃)₂—and —C(CH₃)(C₆H₅)—, R¹¹ and R¹² are each independently an alkyl grouphaving 1 to 4 carbon atoms or halogen atom, and 1 and 1′ are eachindependently an integer of 0 to 4.

[0051] E is the most preferably a group represented by the followingformula.

[0052] In the formula (5), i and j are each a positive integer or 0which ensures that the average value of (i+j) is 0 to 6. The compoundrepresented by the formula (5) is generally obtained as a mixture of aplurality of compounds which differ from one another in i and jexcluding the case where i and j are both “0”. Since it is difficult toisolate these compounds, i and j are expressed by the average value of(i+j). The average value of (i+j) is preferably 2 to 6.

[0053] Illustrative examples of the compound represented by the formula(5) include bisphenol A dimethacrylate,2,2-bis(4-methacryloyloxyethoxyphenyl)propane and2,2-bis(3,5-dibromo-4-methacryloyloxyethoxyphenyl) propane.

[0054] In the above formula (6), R⁹ is a hydrogen atom or methyl group,and F is an alkylene group having 2 to 9 carbon atoms in the main chain,which may have a side chain. Examples of the alkylene group having 2 to9 carbon atoms in the main chain include ethylene group, propylenegroup, trimethylene group, butylene group, neopentylene group, hexylenegroup and nonylene group. When the number of carbon atoms in the mainchain is larger than 9, the homopolymer L-scale Rockwell hardness of theobtained compound tends not to be 60 or more.

[0055] Illustrative examples of the compound represented by the formula(6) include ethylene glycol diacrylate, ethylene glycol dimethacrylate,1,4-butylene glycol dimethacrylate, 1,9-nonylene glycol dimethacrylate,neopentylene glycol dimethacrylate and neopentylene glycol diacrylate.

[0056] In the above formula (7), R¹⁰ is a hydrogen atom, methyl group orethyl group, and k is an integer of 1 to 6. When k is larger than 6, thehomopolymer L-scale Rockwell hardness of the obtained compound tends notto be 60 or more, and k is preferably 3 or 4.

[0057] Illustrative examples of the compound represented by the formula(7) include diethylene glycol dimethacrylate, triethylene glycoldimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycoldimethacrylate and tetrapropylene glycol dimethacrylate.

[0058] These radically polymerizable monomers having a homopolymerL-scale Rockwell hardness of 60 or more may be used alone or incombination of two or more.

[0059] Among the compounds represented by the above formulas (3) to (7)are compounds having a homopolymer L-scale Rockwell hardness of lessthan 60 according to a combination of substituents. The compounds areclassified into a group of low-hardness monomers or medium-hardnessmonomers described after.

[0060] There are high-hardness monomers which are not represented by theabove formulas (3) to (7). Typical examples of the above monomersinclude bisphenol A diglycidyl methacrylate, ethylene glycol bisglycidylmethacrylate and glycidyl methacrylate.

[0061] The curable composition of the present invention preferablycomprises a low-hardness monomer having a homopolymer L-scale Rockwellhardness of 40 or less, in addition to the above high-hardness monomer.

[0062] The low-hardness monomer has the effect of making the curedproduct strong and improving the fading speed of the photochromiccompound.

[0063] The low-hardness monomer is a bifunctional monomer represented bythe following formula (8):

[0064] wherein R¹³ is a hydrogen atom or methyl group, R¹⁴ and R¹⁵ areeach independently a hydrogen atom, methyl group or ethyl group, Z is anoxygen atom or sulfur atom, m is an integer of 1 to 70 when R¹³ is ahydrogen atom and an integer of 7 to 70 when R¹³ is a methyl group, andm′ is an integer of 0 to 70,

[0065] or the following formula (9):

[0066] wherein R¹⁶ is a hydrogen atom or methyl group, R¹⁷ and R¹⁸ areeach independently a hydrogen atom, methyl group, ethyl group orhydroxyl group, I is a divalent organic residual group having a cyclicgroup, and i′ and j′ are each an integer which ensures that the averagevalue of (i′+j′) becomes 8 to 40,

[0067] or a monofunctional monomer represented by the following formula(10):

[0068] wherein R¹⁹ is a hydrogen atom or methyl group, R²⁰ and R²¹ areeach independently a hydrogen atom, methyl group or ethyl group, R²² isa hydrogen atom, alkyl group, alkenyl group, alkoxyalkyl group orhaloalkyl group having 1 to 25 carbon atoms, aryl group having 6 to 25carbon atoms or acyl group other than a (meth)acryloyl group having 2 to25 carbon atoms, Z is an oxygen atom or sulfur atom, m″ is an integer of1 to 70 when R¹⁹ is a hydrogen atom and an integer of 4 to 70 when R¹⁹is a methyl group, and m′″ is an integer of 0 to 70,

[0069] or the following formula (11):

[0070] wherein R²³ is a hydrogen atom or methyl group, R²⁴ is an alkylgroup having 1 to 20 carbon atoms when R is a hydrogen atom and an alkylgroup having 8 to 40 carbon atoms when R²³ is a methyl group.

[0071] In the above formulas (8) to (11), R¹³, R¹⁴, R¹⁹ and R²³ are eacha hydrogen atom or methyl group. That is, the low-hardness monomergenerally has two or less (meth)acryloyloxy groups or (meth)acryloylthiogroups as a polymerizable group.

[0072] In the above formula (8), R¹⁴ and R¹⁵ are each independently ahydrogen atom, methyl group or ethyl group, and Z is an oxygen atom orsulfur atom.

[0073] In the formula (8), when R¹³ is a hydrogen atom, that is, thelow-hardness monomer has an acryloyloxy group or acryloylthio group as apolymerizable group, m is an integer of 7 to 70 and when R¹³ is a methylgroup, that is, the low-hardness monomer has a methacryloyloxy group ormethacryloylthio group as a polymerizable group, m is an integer of 1 to70. Further, m′ is an integer of 0 to 70.

[0074] Illustrative examples of the low-hardness monomer represented bythe above formula (8) include alkylene glycol di(meth)acrylates such astrialkylene glycol diacrylate, tetraalkylene glycol diacrylate,nonylalkylene glycol diacrylate and nonylalkylene glycol dimethacrylate.

[0075] R¹⁶ in the above formula (9) is a hydrogen atom, methyl group orethyl group. I is a divalent organic residual group having a cyclicgroup. I is identical to E having a cyclic group in the above formula(5). i′ and j′ in the formula (9) are each an integer which ensures thatthe average value of (i′+j′) is 8 to 40, preferably 9 to 30. i′ and j′are generally expressed by the average value for the same reason as iand I in the above formula (5).

[0076] Illustrative examples of the low-hardness monomer represented bythe formula (9) include 2,2-bis(4-acryloyloxypolyethylene glycolphenyl)propane having an average molecular weight of 776.

[0077] In the above formula (10), R¹⁹ is a hydrogen atom or methylgroup, and R²⁰ and R²¹ are each independently a hydrogen atom, methylgroup or ethyl group. R²² is a hydrogen atom, alkyl group, alkenylgroup, alkoxyalkyl group or haloalkyl group having 1 to 25 carbon atoms,aryl group having 6 to 25 carbon atoms or acyl group other than a(meth)acryloyl group having 2 to 25 carbon atoms.

[0078] Examples of the alkyl group or alkenyl group having 1 to 25carbon atoms include methyl group, ethyl group, propyl group and nonylgroup. These alkyl groups or alkenyl groups may be linear or branchedand further may be substituted by a substituent such as a halogen atom,hydroxyl group, aryl group or epoxy group.

[0079] Examples of the alkoxyalkyl group having 1 to 25 carbon atomsinclude methoxybutyl group, ethoxybutyl group, butoxybutyl group andmethoxynonyl group.

[0080] Examples of the aryl group having 6 to 25 carbon atoms includephenyl group, toluyl group, anthranyl group or octylphenyl group.Examples of the acyl group other than a (meth)acryloyl group includeacetyl group, propionyl group, butyryl group, valeryl group and oleylgroup.

[0081] In the formula (10), m″ is an integer of 1 to 70 when R¹⁹ is ahydrogen atom, that is, the low-hardness monomer has an acryloyloxygroup or acryloylthio group as a polymerizable group and an integer of 4to 70 when R¹⁹ is a methyl group, that is, the low-hardness monomer hasa methacryloyloxy group or methacryloylthio group as a polymerizablegroup. Further, m′″ is an integer of 0 to 70.

[0082] Illustrative examples of the low-hardness monomer represented bythe formula (10) include polyalkylene glycol (meth)acrylates such aspolyethylene glycol methacrylate having an average molecular weight of526, polyethylene glycol methacrylate having an average molecular weightof 360, methyl ether polyethylene glycol methacrylate having an averagemolecular weight of 475, methyl ether polyethylene glycol methacrylatehaving an average molecular weight of 1,000, polypropylene glycolmethacrylate having an average molecular weight of 375, polypropylenemethacrylate having an average molecular weight of 430, polypropylenemethacrylate having an average molecular weight of 622, methyl etherpolypropylene glycol methacrylate having an average molecular weight of620, polytetramethylene glycol methacrylate having an average molecularweight of 566, octylphenyl ether polyethylene glycol methacrylate havingan average molecular weight of 2,034, nonylether polyethylene glycolmethacrylate having an average molecular weight of 610, methyl etherpolyethylene thioglycol methacrylate having an average molecular weightof 640 and perfluoroheptyl ethylene glycol methacrylate having anaverage molecular weight of 498.

[0083] In the above formula (11), R²³ is a hydrogen atom or methylgroup, and R²⁴ is an alkyl group having 1 to 20 carbon atoms when R²³ isa hydrogen atom and an alkyl group having 8 to 40 carbon atoms when R²³is a methyl group.

[0084] These alkyl groups may be linear or branched and further may besubstituted by a substituent such as halogen atom, hydroxyl group,alkoxyl group, acyl group or epoxy group.

[0085] Illustrative examples of the low-hardness monomer represented bythe formula (11) include stearyl methacrylate, lauryl methacrylate,ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylateand lauryl acrylate.

[0086] Out of the low-hardness monomers represented by the aboveformulas (8) to (11), methyl ether polyethylene glycol methacrylatehaving an average molecular weight of 475, methyl ether polyethyleneglycol methacrylate having an average molecular weight of 1,000,trialkylene glycol diacrylate, tetraalkylene glycol diacrylate,nonylalkylene glycol diacrylate, methyl acrylate, ethyl acrylate, butylacrylate and lauryl acrylate are particularly preferred.

[0087] These radically polymerizable monomers having a homopolymerL-scale Rockwell hardness of 40 or less may be used alone or incombination of two or more.

[0088] Among the compounds represented by the above formulas (8) to (11)are compounds having a homopolymer L-scale Rockwell hardness of 40 ormore according to a combination of substituents. These compounds areclassified as high-hardness monomers described above or medium-hardnessmonomers which will be described hereinafter.

[0089] In the composition of the present invention, a monomer which isneither a high-hardness monomer nor a low-hardness monomer describedabove, that is, a monomer having a homopolymer L-scale Rockwell hardnessof more than 40 and less than 60 (to be also referred to as“medium-hardness monomer”) may be used. Examples of the medium-hardnessmonomer include bifunctional (meth)acrylates such as polytetramethyleneglycol dimethacrylate having an average molecular weight of 650,polytetramethylene glycol dimethacrylate having an average molecularweight of 1,400, and bis (2-methacryloyloxyethylthioethyl) sulfide;polyallyl compounds such as diallyl phthalate, diallyl isophthalate,diallyl tartarate, diallyl epoxysuccinate, diallyl fumarate, diallylchlorendate, diallyl hexaphthalate and allyl diglycol carbonate;polythioacrylic and polythiomethacrylic acid ester compounds such as1,2-bis(methacryloylthio)ethane, bis(2-acryloylthioethyl)ether and1,4-bis(methacryloylthiomethyl)benzene; unsaturated carboxylic acidssuch as acrylic acid, methacrylic acid and maleic anhydride; acrylic andmethacrylic acid ester compounds such as methyl methacrylate, butylmethacrylate, benzyl methacrylate, phenyl methacrylate, 2-hydroxyethylmethacrylate and biphenyl methacrylate; fumaric acid ester compoundssuch as diethyl fumarate and diphenyl fumarate; thioacrylic andthiomethacrylic acid ester compounds such as methyl thioacrylate, benzylthioacrylate and benzyl thiomethacrylate; vinyl compounds such asstyrene, chlorostyrene, methylstyrene, vinylnaphthalene, α-methylstyrenedimmer, bromostyrene, divinylbenzene and vinylpyrrolidone; and radicallypolymerizable monofunctional monomers such as (meth)acrylates whosehydrocarbon chain having an unsaturated bond in the molecule has 6 to 25carbon atoms, exemplified by oleyl methacrylate, nerol methacrylate,geraniol methacrylate, linalool methacrylate and farnesol methacrylate.

[0090] The above high-hardness monomer, low-hardness monomer andmedium-hardness monomer may be suitably mixed together before use. Inorder to well balance the characteristic properties such as solventresistance, hardness and heat resistance, or photochromic propertiessuch as color development intensity and fading speed of a cured productof the curable composition, it is preferred that a low-hardness monomerbe contained in an amount of 5 to 70 wt % and a high-hardness monomer becontained in an amount of 5 to 95 wt % based on the total of all theradically polymerizable monomers. Particularly preferably, a monomerhaving three or more radically polyemrizable groups is contained as thehigh-hardness monomer in an amount of at least 5 wt % based on the totalof all the radically polymerizable monomers.

[0091] The radically polymerizable monomers of the present inventionpreferably include a radically polymerizable monomer having at least oneepoxy group and at least one radically polymerizable group in themolecule (to be simply referred to as “epoxy-based monomer” hereinafter)besides the above monomers classified by hardness. The epoxy-basedmonomer may have a homopolymer L-scale Rockwell hardness of 60 or moreor 40 or less based on its structure. It is classified as ahigh-hardness monomer, low-hardness monomer or medium-hardness monomeraccording to the hardness of its homopolymer.

[0092] By using the epoxy-based monomer as one of the radicallypolymerizable monomers in the present invention, the durability of thephotochromic compound can be improved and further the adhesion of thephotochromic compound can be improved when it is used as a coatingcomposition.

[0093] Known compounds may be used as the epoxy-based monomer butcompounds having a (meth)acryloyloxy group as a radically polymerizablegroup are preferred.

[0094] A monomer preferably used as the epoxy-based monomer isrepresented by the following formula (12):

[0095] wherein R²⁵ and R²⁸ are each independently a hydrogen atom ormethyl group, R²⁶ and R²⁷ are each independently an alkylene grouphaving 1 to 4 carbon atoms or a group represented by the followingformula, and s and t are each independently an integer of 0 to 10,

[0096] wherein G′ is an oxygen atom, sulfur atom or group selected fromthe group consisting of —S(O₂)—, —C(O)—, —CH₂—, —CH═CH—, —C(CH₃)₂— and—C(CH₃) (C₆H₅)—, R²⁹ and R³⁰ are each independently an alkyl grouphaving 1 to 4 carbon atoms or halogen atom, and 1″ and 1′″ are eachindependently an integer of 0 to 4.

[0097] Examples of the alkylene group having 1 to 4 carbon atomsrepresented by R²⁶ and R²⁷ include methylene group, ethylene group,propylene group, trimethylene group and butylene group. These alkylenegroups may be substituted by a hydroxyl group or halogen atom.

[0098] When R²⁶ and/or R²⁷ are/is a group represented by the followingformula, G′ is an oxygen atom, sulfur atom or group selected from thegroup consisting of —S(O₂)—, —C(O)—, —CH₂—, —CH═CH—, —C(CH₃)₂— and—C(CH₃)(C₆H₅)—, R²⁹ and R³⁰ are each independently an alkyl group having1 to 4 carbon atoms, such as methyl group, ethyl group, propyl group orbutyl group, or halogen atom such as chlorine atom or bromine atom, and1″ and 1′″ are each independently an integer of 0 to 4.

[0099] The group represented by the above formula is the most preferablya group represented by the following formula.

[0100] Illustrative examples of the epoxy-based monomer represented bythe above formula (12) include glycidyl acrylate, glycidyl methacrylate,β-methylglycidyl methacrylate, bisphenol A-monoglycidylether-methacrylate, 4-glyhcidyloxy methacrylate,3-(glycidyl-2-oxyethoxy)-2-hydroxypropyl methacrylate,3-(glycidyloxy-1-isopropyloxy)-2-hydroxypropyl acrylate,3-glycidyloxy-2-hydroxypropyloxy)-2-hydroxypropyl acrylate andglycidyloxy polyethylene glycol methacrylate having an average molecularweigh of 540. Out of these, glycidyl acrylate, glycidyl methacrylate andglycidyloxy polyethylene glycol methacrylate having an average molecularweight of 540 are particularly preferred.

[0101] The amount of the epoxy-based monomer is preferably 0.01 to 30 wt%, particularly preferably 0.1 to 20 wt % based on the total of all theradically polymerizable monomers.

[0102] The curable composition of the present invention may furthercomprise a radically polymerizable monomer having a silanol group or agroup which forms a silanol group through hydrolysis (may be referred toas “silyl monomer” hereinafter) or a radically polymerizable monomerhaving an isocyanate group (may be referred to as “isocyanate monomer”hereinafter) to improve the hard coating properties of a cured coatingfilm or adhesion between a cured coating film and a substrate such as aspectacle lens when the composition is used as a coating.

[0103] Any known compound having a silanol group (≡Si—OH) or a groupwhich forms a silanol group through hydrolysis and a radicallypolymerizable group may be used as the silyl monomer.

[0104] Examples of the group which forms a silanol group throughhydrolysis include alkoxysilyl group (≡Si—O—R; R is an alkyl group),aryloxysilyl group (≡Si—O—Ar; Ar is an aryl group which may besubstituted), halosilyl group (≡Si—X; X is a halogen atom) andsilyloxysilyl group (disiloxane bond; ≡Si—O—Si≡).

[0105] Out of the above groups which form a silanol group throughhydrolysis, alkoxysilyl group and silyloxysilyl group are preferred,alkoxysilyl group including an alkoxyl group having 1 to 4 carbon atomsis more preferred, and methoxysilyl group and ethoxysilyl group are themost preferred because a silanol group is easily formed, synthesis andpreservation are easy and a group eliminated from a silicon atom by areaction has little influence upon the physical properties of the curedproduct.

[0106] Examples of the radically polymerizable group include knownradically polymerizable groups such as (meth)acryloyl group,(meth)acryloyl group derivatives such as (meth)acryloyloxy group,(meth)acryloylamino group and (meth)acryloylthio group, vinyl group,allyl group and styryl group. When the radically polymerizable group isa vinyl group, allyl group or styryl group, it may have a substituent.Examples of the substituent include alkyl groups and haloalkyl groupshaving 1 to 4 carbon atoms such as methyl group, ethyl group, propylgroup, butyl group, chloromethyl group and trifluoromethyl group,halogen atom, cyano group, nitro group and hydroxyl group. When theradically polymerizable group is a (meth)acryloylamino group, an organicgroup such as substituted or nonsubstituted alkyl group, aryl group orallyl group may be bonded to the amidonitrogen atom of the group, inaddition to a (meth)acryloyl group and the above silanol group or groupwhich forms a silanol group through hydrolysis.

[0107] Out of the radically polymerizable groups, (meth)acryloyl groupand (meth)acryloyloxy group are preferred, and (meth)acryloyloxy groupis more preferred from the viewpoints of easy acquisition and highpolymerizability.

[0108] Preferred silyl monomers having the group capable of forming asilanol group through hydrolysis and a radically polymerizable group arerepresented by the following formulas (13) to (15):

[0109] wherein R³¹ is an alkyl group or aryl group, R³² and R³³ are eachindependently an alkyl group, aryl group or acyl group, A is a divalentto tetravalent organic residual group, Y is a radically polymerizablegroup, a is an integer of 1 to 3, b is an integer of 0 to 2, c is aninteger of 0 to 2, d is an integer of 1 to 3, and e is an integer of 1to 3, with the proviso that (a+b+c+d)=4,

[0110] wherein R³² and R³³ are each independently an alkyl group, arylgroup or acyl group, A is a divalent to tetravalent organic residualgroup, Y is a radically polymerizable group, b is an integer of 0 to 2,c is an integer of 0 to 2, d is an integer of 1 to 3, and e is aninteger of 1 to 3, with the proviso that (b+c+d)=3,

[0111] wherein R³¹ is an alkyl group or aryl group, R³² and R³³ are eachindependently an alkyl group, aryl group or acyl group, R³⁴ is a vinylgroup, a is an integer of 1 to 3, b is an integer of 0 to 2, c is aninteger of 0 to 2, and d is an integer of 1 to 3, with the proviso that(a+b+c+d)=4.

[0112] In the above formulas (13) and (15), R³¹ is an alkyl group oraryl group. It is preferably an alkyl group having 1 to 10 carbon atomsin the main chain or an aryl group having 6 to 10 carbon atoms asmembers of a ring because they can easily form a silanol group throughhydrolysis and have keeping stability. The alkyl group or aryl group mayhave a substituent. Examples of the substituent include alkyl groupshaving 1 to 10 carbon atoms such as methyl group, ethyl group and propylgroup, haloalkyl groups having 1 to 10 carbon atoms such as chloromethylgroup and trifluoromethyl group, alkoxyl groups having 1 to 10 carbonatoms such as methoxy group, ethoxy group and butoxy group, acyl groupshaving 2 to 10 carbon atoms such as acetyl group, propionyl group, oleylgroup and benzoyl group, amino group, alkyl-substituted amino groupshaving 1 to 10 carbon atoms such as methylamino group, ethylamino group,dimethylamino group and diethylamino group, halogen atoms such asfluorine atom, chlorine atom and bromine atom, hydroxyl group, carboxylgroup, mercapto group, cyano group and nitro group.

[0113] Examples of the substituted or nonsubstituted alkyl group having1 to 10 carbon atoms in the main chain include methyl group, ethylgroup, propyl group, butyl group and chloromethyl group. Examples of thesubstituted or nonsubstituted aryl group having 6 to 10 carbon atoms asmembers of a ring include phenyl group, toluyl group and xylyl group.

[0114] R³¹ is preferably an alkyl group, more preferably an alkyl grouphaving 1 to 4 carbon atoms, the most preferably methyl group or ethylgroup from the viewpoints of formation ease of a silanol group throughhydrolysis and keeping stability.

[0115] In the above formulas (13) to (15), R³² and R³³ are eachindependently an alkyl group, aryl group or acyl group. Examples of thealkyl group and aryl group are the same as those listed for R¹ andpreferred examples thereof are the same as those listed for R¹. The acylgroup is preferably an acyl group having 2 to 10 carbon atoms. The acylgroup may be an aliphatic acyl group or aromatic acyl group. Examples ofthe acyl group include acetyl group, propionyl group and benzoyl group.

[0116] In the above formulas (13) and (14), A is a divalent totetravalent organic residual group, preferably a divalent to tetravalentorganic residual group having 1 to 30 carbon atoms. The organic residualgroup is not limited to a particular structure and may have a side chainor a substituent. It also may have a bond other than a carbon-carbonbond, such as ether bond, ester bond, amide bond, amino bond, urethanebond, thioether bond or sulfonyl bond in the structure and may furthercontain an oxo group (ketone carbon). Preferred examples of thesubstituent of the organic residual group include halogen atoms such asfluorine atom, chlorine atom and bromine atom, hydroxyl group, aminogroup, mercapto group, cyano group and nitro group.

[0117] The organic residual group is preferably an organic residualgroup having 1 to 10 carbon atoms, as exemplified by alkylene groupshaving 1 to 10 carbon atoms such as methylene group, ethylene group,propylene group, trimethylene group and butylene group, alkylenedioxygroups having 1 to 10 carbon atoms such as methylenedioxy group,ethylenedioxy group, propylenedioxy group and butylenedioxy group, andgroups shown below (in the below formulas, n is an integer of 1 to 5,and n′ and n″ are each an integer of 1 to 3).

[0118] What are obtained by substituting these groups by the abovesubstituent may also be used as the organic residual group.

[0119] Y in the above formulas (13) and (14) is a radicallypolymerizable group selected from (meth)acryloyl group, (meth)acryloylgroup derivatives such as (meth)acryloyloxy group, (meth)acryloylaminogroup and (meth)acryloylthio group, substituted and nonsubstituted vinylgroups, substituted and nonsubstituted allyl groups, and substituted andnonsubstituted styryl groups. It is preferably a (meth)acryloyl group or(meth)acryloyloxy group.

[0120] Out of the silyl monomers represented by the above formulas,silyl monomers represented by the formula (13) are preferred, and silylmonomers represented by following formula (16) are particularlypreferred:

[0121] wherein R³⁵ is a hydrogen atom or methyl group, R³⁶ is analkylene group having 1 to 10 carbon atoms, R³⁷ is an alkoxyl grouphaving 1 to 4 carbon atoms, R³⁸ is an alkyl group having 1 to 4 carbonatoms, a is an integer of 1 to 3, and b is an integer of 0 to 2, withthe proviso that (a+b)=3.

[0122] Examples of the alkylene group having 1 to 10 carbon atomsrepresented by R³⁵ in the above formula (16) include ethylene group,propylene group, trimethylene group and butylene group. Examples of R³⁷include methoxy group, ethoxy group, propoxy group and butoxy group.Examples of R³⁸ include methyl group, ethyl group, propyl group andbutyl group.

[0123] Illustrative examples of the silyl monomers represented by theabove formulas (13) to (15) includeγ-methacryloyloxypropyltrimethoxysilane,γ-methacryloyloxypropyltriethoxysilane,γ-methacryloyloxypropylmethyldimethoxysilane,(3-acryloxypropyl)dimethylmethoxysilane,(3-acryloxypropyl)methyldimethoxysilane,(3-acryloxypropyl)trimethoxysilane,3-(N-allylamino)propyltrimethoxysilane, allyldimethoxysilane,allyltriethoxysilane, allyltrimethoxysilane,3-aminophenoxydimethylvinylsilane, 4-aminophenoxydimethylvinylsilane,3-(3-aminopropoxy)-3,3-dimethyl-1-propenyltrimethoxysilane,butenyltriethoxysilane, 2-(chloromethyl)allyltrimethoxysilane,diethoxyvinylsilane, 1,3-divinyltetraethoxydisiloxane,docosenyltriethoxysilane,o-(methacryloxyethyl)-N-(triethoxysilylpropyl)urethane,N-(3-methacryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane,methacryloxyethoxytrimethylsilane,(methacryloxymethyl)dimethylethoxysilane,methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxypropyldimethylethoxysilane,methacryloxypropyldimethylmethoxysilane,methacryloxypropyltris(methoxyethoxy)silane, 7-octenyltrimethoxysilane,1,3-bis(methacryloxy)-2-trimethylsiloxypropane,tetrakis(2-methacryloxyethoxy)silane, trivinylethoxysilane,trivinylmethoxysilane, vinyldimethylethoxysilane,vinyldiphenylethoxysilane, vinylmethyldiacetoxysilane,vinylmethyldiethoxysilane, vinylmethyldimethoxysilane,o-(vinyloxyethyl)-N-(triethoxysilylpropyl)urethane,vinyloxytrimethylsilane, vinylphenyldiethoxysilane,vinylphenylmethylmethoxysilane, vinyltriacetoxysilane,vinyltri-t-butoxysilane, vinyltriethoxysilane,vinyltriisopropenoxysilane, vinyltriisopropoxysilane,vinyltrimethoxysilane, vinyltriphenoxysilane andvinyltris(2-methoxyethoxy)silane.

[0124] Out of these, silyl monomers represented by the above formula(16) such as γ-methacryloyloxypropyltrimethoxysilane,γ-methacryloyloxypropyltriethoxysilane,γ-methacryloyloxypropylmethyldimethoxysilane,(3-acryloxypropyl)dimethylmethoxysilane,(3-acryloxypropyl)methyldimethoxysilane,(3-acryloxypropyl)trimethoxysilane,(methacryloxymethyl)dimethylethoxysilane,methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxypropyldimethylethoxysilane andmethacryloxypropyldimethylmethoxysialne are particularly preferred.

[0125] In the present invention, adhesion to a substrate and a hard coatmaterial can be improved by using an isocyanate monomer in place of theabove silyl monomer.

[0126] Any known compound having an isocyanate group (—NCO) and aradically polymerizable group may be used as the isocyanate monomer.

[0127] The isocyanate monomer may be represented by the followingformula (17) or (18):

[0128] wherein R³⁹ is a hydrogen atom or methyl group, and R⁴⁰ is analkylene group,

[0129] wherein R⁴¹ is a hydrogen atom or methyl group, and R⁴² is analkylene group.

[0130] In the above formulas (17) and (18), R⁴⁰ and R⁴² are both analkylene group. The alkylene group is preferably an alkylene grouphaving 1 to 10 carbon atoms. Examples of the alkylene group includemethylene group, ethylene group, propylene group, trmiethylene group andbutylene group.

[0131] Preferred examples of the isocyanate monomer include2-isocyanatoethoxymethacrylate and 4-(2-isocyanatoisopropyl)styrene.

[0132] The amount of the silyl monomer or isocyanate monomer in thepresent invention is not particularly limited. However, when the abovemonomer is added to improve adhesion to a substrate such as a spectaclelens and a hard coat material, its amount is preferably 0.5 to 20 wt %,more preferably 1 to 10 wt % based on the total of all the radicallypolymerizable monomers so as to improve scratching resistance at thetime of forming a hard coat or photochromism such as color developmentintensity or fading speed.

[0133] These silyl monomers or isocyanate monomers may be used alone orin combination of two or more. Also, a mixture of a silyl monomer and anisocyanate monomer may be used.

[0134] When a silyl monomer or isocyanate monomer is to be added to theradically polymerizable monomers, an amine compound is preferably addedas a catalyst besides the radically polymerizable monomers. By adding anamine compound, when the obtained composition is used as the curablecomposition or coating composition of the present invention, adhesionbetween a cured coating layer of the curable composition or coatingcomposition and a hard coat layer or a substrate can be greatlyimproved.

[0135] Any known basic amine compound can be used as the amine compoundused in the present invention if it serves as a condensation or additioncatalyst for the above silyl monomer or isocyanate monomer. However,hindered amine compounds having an amino group represented by thefollowing formula as the sole amino group are excluded because theydon't have the above catalytic function:

[0136] wherein R⁰¹ is a hydrogen atom or alkyl group, R⁰², R⁰³, R⁰⁴ andR⁰⁵ are the same or different alkyl groups.

[0137] Preferred examples of the amine compound which can be suitablyused in the present invention include nonpolymerizable low-molecularamine compounds such as triethanolamine, N-methyldiethanolamine,triisopropanolamine, 4,4-dimethylaminobenzophenone anddiazabicyclooctane, amine compounds having a polymerizable group such asN,N-dimethylaminoethyl methacrylate and N,N-diethylaminoethylmethacrylate, and amine compounds having a silyl group such asn-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane,dimethoxyphenyl-2-piperidinoethoxysilane,N,N-diethylaminomethyltrimethylsilane and(N,N-diethyl-3-aminopropyl)trimethoxysilane.

[0138] Out of the above preferred amine compounds, amine compoundshaving a hydroxyl group, (meth)acryloyloxy group as a radicallypolymerizable group or group capable of forming a silanol group throughhydrolysis are preferred from the viewpoint of the improvement ofadhesion. For example, amine compounds represented by the followingformula (19) are preferred because they have high basicity and a highadhesion improving effect:

[0139] wherein R⁰⁶ is a hydrogen atom or linear alkyl group having 1 to4 carbon atoms, R⁰⁷ is a hydroxyl group, (meth)acryloyloxy group orgroup capable of forming a silanol group through hydrolysis, R⁰⁸ is ahydrogen atom, alkyl group having 1 to 6 carbon atoms, hydroxyl group,(meth)acryloyloxy group or group capable of forming a silanol groupthrough hydrolysis, A′ is an alkylene group having 2 to 6 carbon atoms,and A″ is an alkylene group having 1 to 6 carbon atoms when R⁰⁸ is ahydrogen atom or alkyl group and an alkylene group having 2 to 6 carbonatoms when R⁰⁸ is a hydroxyl group, (meth)acryloyloxy group or groupcapable of forming a silanol group through hydrolysis.

[0140] The group capable of forming a silanol group through hydrolysisrepresented by R⁰⁷ and R⁰⁸ in the above formula (19) is identical to thegroup defined for the above silyl monomer.

[0141] These amine compounds may be used alone or in combination of twoor more. The amount of the amine compound is preferably 0.01 to 20 partsby weight based on 100 parts by weight of the total of all the radicallypolymerizable monomers when it is used as a catalyst. It is morepreferably 0.1 to 10 parts by weight, much more preferably 1 to 10 partsby weight. When the amount is smaller than 0.01 part by weight or largerthan 20 parts by weight, it is difficult to obtain the effect ofimproving adhesion between the coating layer and the substrate. Furtherwhen the amount is larger than 20 parts by weight, the coating layertends to yellow disadvantageously.

[0142] 100 parts by weight of a polymer compound may be used in place of100 parts by weight of the above radically polymerizable monomer as thesolvent for a molecular compound in the photochromic compound of thepresent invention. The polymer compound is mixed with the molecularcompound as a molten product or a solution thereof.

[0143] A known thermoplastic resin may be used as the polymer compound.When the above cured product is used as an optical material, methylpolyacrylate, ethyl polyacrylate, methyl polymethacrylate, ethylpolymethacrylate, polystyrene, polyacrylonitrile, polyvinyl alcohol,polyacrylamide, poly(2-hydroxyethylmethacrylate), polydimethylsiloxaneor polycarbonate is preferably used because they have excellent opticalproperties.

[0144] When the polymer compound is used in the form of a solution, aknown organic solvent which is known to dissolve a polymer compound canbe used according to the type of the polymer compound in use. Theconcentration of the polymer compound in the polymer compound solutionis not particularly limited. For example it may be suitably determinedin consideration of moldability and operation efficiency when a film ismolded by a casting method or coated.

[0145] The photochromic composition of the present invention is obtainedby mixing 100 parts by weight of the solvent for a molecular compoundcomprising the radically polymerizable monomer(s) or the moltenpolymer(s) or a solution of the polymer compound(s) with 0.01 to 20parts by weight of “a molecular compound comprising a chromene compoundand an aromatic compound”. The molecular compound is a compound which isproduced by directly bonding the same or different types of stablemolecules in a certain ratio, bonding between molecules constituting themolecular compound is gentle and the original structure and bondingproperty of each constituent molecule rarely change, and which can bedissociated into original constituent molecules relatively easily. Ingeneral, the molecular compound is a solid in which constituentmolecules are arranged in a certain ratio. When the molecular compoundand each constituent molecule are compared with each other, they differin physical property values such as melting point, boiling point andsolubility. When the amount of the molecular compound to be mixed issmaller than 0.01 part by weight, satisfactory photochromism cannot beobtained and when the amount is larger than 20 parts by weight, it isdifficult to dissolve the molecular compound uniformly. The amount ofthe molecular compound is preferably 0.05 to 15 parts by weight,particularly preferably 0.1 to 5 parts by weight based on 100 parts byweight of the solvent for a molecular compound from the viewpoints ofphotochromism and acquisition ease of a uniform solution.

[0146] The above molecular compound used in the present invention is notparticularly limited if it is a molecular compound consisting of achromene compound and an aromatic compound as constituent components andmay be a molecular compound consisting of several chromene compounds andseveral aromatic compounds. The bonding manner of the constituentmolecules is not limited and the ratio of the constituent molecules isnot limited as well. The ratio is determined for each combination of achromene compound and an aromatic compound. In the molecular compoundwhich is the photochromic compound of the present invention, the ratioof the number of moles of the chromene compound to the number of molesof the aromatic compound is generally 5:1 to 1:10.

[0147] The chromene compound which is one of the constituent componentsof the molecular compound as the photochromic compound of the presentinvention is not particularly limited if it can form a molecularcompound with an aromatic compound. However, it is preferably a chromenecompound having at least one substituted or nonsubstituted phenyl groupbecause it can easily form a molecular compound with an aromaticcompound. It is considered that a molecular compound is easily formed bya π electron-π electron interaction between the above substituted phenylgroup of the chromene compound and the aromatic compound.

[0148] In the present invention, chromene compounds represented by thefollowing formula (1) are particularly preferred out of the chromenecompounds having at least one substituted or nonsubstituted phenyl groupbecause they exhibit excellent photochromism:

[0149] R¹ and R² in the above formula (1) are each a substituted ornonsubstituted aryl group, or a substituted or nonsubstituted aromaticheterocyclic group, and the divalent group represented by the followingformula (2) is a divalent condensed polycyclic organic group which has abenzene ring condensed to a 2H-pyran ring in the above formula (1) andmay have a substituent.

[0150] Examples of the nonsubstituted aryl group and the nonsubstitutedaromatic heterocyclic group represented by R¹ or R² include phenylgroup, 1- or 2-naphthyl group, 2- or 3-furyl group, 2- or 3-thienylgroup and 2- or 3-pyrrolidyl group.

[0151] The substituent of the substituted aryl group and the substitutedor nonsubstituted aromatic heterocyclic group represented by R¹ or R²are not particularly limited but preferably at least one selected fromthe group consisting of alkyl group, alkoxy group, aralkoxy group,substituted or nonsubstituted amino group, cyano group, substituted ornonsubstituted aryl group, fluorine atom, chlorine atom, bromine atom,iodine atom, aralkyl group, trifluoromethyl group, trifluoromethoxygroup, cyanomethyl group, arylsulfonyl group and alkylsulfonyl group.Examples of the substituent of the above substituted aryl group are thesame as those listed for the substituent of the substituted aryl grouprepresented by R¹ or R² excluding the substituted aryl group. Examplesof the substituent in the substituted amino group include the aboveexamples of the substituent of the substituted aryl group, substitutedor nonsubstituted heterocyclic group having a nitrogen atom as a heteroatom and bonded to a phenyl group by the nitrogen atom, and fusedheterocyclic group having an aromatic hydrocarbon ring or aromatichetero ring condensed to the heterocyclic ring. A hetero atom such asoxygen atom, sulfur atom or nitrogen atom may be existent in the heteroring besides the nitrogen atom bonded to a phenyl group.

[0152] One of R¹ and R² in the above formula (1) is preferably a phenylgroup substituted by a substituted or nonsubstituted amino group fromthe viewpoint of photochromism. Preferred examples of the substituted ornonsubstituted amino group include amino group; alkylamino groups suchas methylamino group, ethylamino group, n-propylamino group,i-propylamino group, n-butylamino group and t-butylamino group;dialkylamino groups such as dimethylamino group, diethylamino group,di-n-propylamino group, di-1-propylamino group, di-n-butylamino groupand di-t-butylamino group; arylamino groups such as phenylamino groupand naphthylamino group; diarylamino groups such as diphenylamino group;and “substituted or nonsubstituted heterocyclic group having a nitrogenatom as a hetero atom and bonded to a phenyl group by the nitrogen atom,or fused heterocylic group having an aromatic hydrocarbon ring oraromatic hetero ring condensed to the heterocylic group” having 2 to 10carbon atoms, particularly 2 to 6 carbon atoms as members of aheterocyclic group, such as morpholino group, piperidino group,pyrrolidinyl group, piperazino group, N-methylpiperazino group andindolinyl group.

[0153] The divalent group represented by the above formula (2) in theabove formula (1) is a divalent condensed polycyclic organic group whichmay have a substituent and contains a benzene ring condensed to a2H-pyran ring in the above formula (1). The group is not particularlylimited if a chromene compound bonded to the group exhibitsphotochromism but preferably a group represented by the followingformula (20), (21), (22) or (23) because it exhibits excellentphotochromism:

[0154] R⁴³ and R⁴⁴ in the above formula (20) are each independently ahydrogen atom, alkyl group, alkoxy group, aralkyloxy group, aralkylgroup, carboxy group, alkoxycarbonyl group, aryloxycarbonyl group whichmay have a substituent, aralkyloxycarbonyl group, amino group which mayhave a substituent, cyano group, nitro group, aryl group which may havea substituent, halogen atom, heterocyclic group which has a nitrogenatom as a hetero atom and may have a substituent bonded to the ring of acondensed polycyclic organic group by the nitrogen atom, or fusedheterocyclic group having an aromatic hydrocarbon ring or aromatichetero ring bonded to the heterocyclic group. aa indicative of thenumber of bonded R⁴³'s is an integer of 0 to 3, and 11 indicative of thenumber of bonded R⁴⁴'s is an integer of 0 to 2. When aa or 11 is 2 ormore, bonded R⁴³'s or R⁴⁴'s may be the same or different. When R⁴³ andR⁴⁴ may have a substituent, the substituent is at least one selectedfrom the group consisting of alkyl group, alkoxy group, aryl group andhalogen atom.

[0155] In the above formula (21), R⁴⁵ and R⁴⁶ are the same as R⁴³ andR⁴⁴ in the above formula (20), respectively, mm indicative of the numberof bonded R⁴⁵'s is an integer of 0 to 2, and bb indicative of the numberof bonded R⁴⁶'s is an integer of 0 to 3. When mm or bb is 2 or more,bonded R⁴⁵'s or R⁴⁶'s may differ from each other.

[0156] In the above formula (22), R⁴⁷ and R⁴⁸ are the same as R⁴³ andR⁴⁴ in the above formula (20), respectively, and cc and dd indicative ofthe number of bonded R⁴⁷'s and R⁴⁸ 's are each an integer of 0 to 3.When cc or dd are 2 or more, bonded R⁴⁷'s or R⁴⁸'s may differ from eachother.

[0157] The group represented by the following formula (24) in the aboveformula (23) is an aromatic hydrocarbon group or unsaturatedheterocyclic group, and R⁴⁹ and R⁵⁰ are the same as R⁴³ and R⁴⁴ in theabove formula (20), respectively.

[0158] ee and ff indicative of the number of bonded R⁴⁹'s and R⁵⁰'s areeach an integer of 0 to 3. When ee or ff are 2 or more, bonded R⁴⁹'s orR⁵⁰'s may differ from each other. R⁵¹ and R⁵² are each independently ahydrogen atom, hydroxyl group, alkyl group, alkoxy group, aralkyloxygroup, aralkyl group, carboxy group, alkoxycarbonyl group,aryloxycarbonyl group, aralkyloxycarbonyl group, substituted ornonsubstituted amino group, cyano group, nitro group, substituted ornonsubstituted aryl group, or bonded together to form an oxo group,vinylene group which may have a substituent, heterocyclic group whichhas 1 or 2 oxygen atoms and may have a substituent, aliphatichydrocarbon ring group which may have a substituent, or a group forminga group represented by the following formula (25):

[0159] wherein —Y— is represented by any one of the following formulas:

[0160] wherein Z¹ and Z² are each independently an oxygen atom or sulfuratom, R⁵³, R⁵⁴, R⁵⁵ and R⁵⁶ are each an alkylene group, and gg, hh, iiand jj are each an integer of 1 to 4.

[0161] Illustrative examples of the “chromene compound having at leastone substituted or nonsubstituted phenyl group” suitable as the chromenecompound of the present invention are given below.

[0162] The above chromene compounds are disclosed in the pamphlet ofWO98/45281, the pamphlet of WO96/14596, German Laid-open PatentApplication DE19902771 A1, the pamphlet of WO98/04937 and the like.

[0163] The aromatic compound which is the other constituent molecule ofthe molecular compound is not particularly limited if it can form themolecular compound with the above chromene compound. However, it ispreferably an aromatic compound having a molecular weight of 70 to 150when the chromene compound has a molecular weight of 300 to 800 becausethey easily form a molecular compound. It is considered that this isbecause the aromatic compound can be situated at a position where sterichindrance more hardly occurs and the above π electron-π electroninteraction more readily occurs as the molecular weight of the aromaticcompound becomes lower. Illustrative examples of the aromatic compoundwhich can be suitably used include toluene, benzene, chlorobenzene,dichlorobenzene, naphthalene, thiophene and pyrrole.

[0164] That is, it can be said that a molecular compound of a chromenecompound having at least one substituted or nonsubstituted phenyl group,particularly a chromene compound having a molecular weight of 300 to 800represented by the above formula (1), and an aromatic compound having amolecular weight of 70 to 0.150 is preferably used as the abovemolecular compound used as the photochromic material of the presentinvention from the viewpoints of photochromism and synthesis ease.

[0165] The molecular compound of the chromene compound represented bythe above formula (1) and the aromatic compound having a molecularweight of 70 to 150 has been unknown and the existence and utilitythereof have been discovered by the inventors of the present inventionfor the first time. The process for producing this molecular compound isnot particularly limited. However, the molecular compound can besuitably produced by contacting the aromatic compound having a molecularweight of 70 to 150 to the chromene compound represented by the aboveformula (1) in a solution to form a molecular compound of the chromenecompound and the aromatic compound and precipitating the crystal of theformed molecular compound. As means of contacting the aromatic compoundhaving a molecular weight of 70 to 150 to the chromene compound in thesolution, there are (i) a method in which the chromene compound and thearomatic compound are mixed together and heated as required to dissolvethe chromene compound in the aromatic compound so as to prepare auniform solution, and (ii) a method in which the chromene compound andthe aromatic compound are mixed with an organic solvent which dissolvesboth to dissolve the both compounds so as to prepare a uniform solution.In either case, the both compounds are made coexistent in the solution,thereby naturally forming a molecular compound. To take out the formedmolecular compound, the solution is concentrated as required and cooledto precipitate the molecular compound as a crystal, or a poor solvent isadded to the solution to precipitate the molecular compound as acrystal, and the precipitated crystal is separated by filtration or thelike and taken out. A high-purity molecular compound can be obtained byemploying these crystallization methods. When the total amount ofimpurities contained in the solution is small, the solvent is distilledoff under conditions which ensure that the molecular compound does notdecompose to recover the molecular compound.

[0166] In the above methods, the molar ratio of the chromene compound tothe aromatic compound to be contacted to each other in the solution isnot particularly limited. As a surplus of the aromatic compound can beeasily removed, it is preferred to use an excessive amount, particularly10 to 1,000 moles of the aromatic compound based on 1 mole of thechromene compound from the viewpoint of reaction efficiency. In theabove methods, chromene compounds and aromatic compounds may be usedalone or in combination.

[0167] The molecular compound of the present invention obtained by theabove methods is existent as a solid at normal temperature and normalpressure and can be confirmed by the following means (a) to (c).

[0168] (a) The melting point of the molecular compound is measured andthe measured melting point differs from the phase transition points(melting points or boiling points) of the chromene compound and thearomatic compound forming the molecular compound.

[0169] (b) The proton nuclear magnetic resonance spectrum (¹H-NMR) ofthe molecular compound is measured and the proton integral ratios ofintrinsic peaks of the chromene compound and the aromatic compoundforming the molecular compound are compared with each other to determinethe molar ratio of the chromene compound to the aromatic compound.

[0170] (c) The ratio of the chromene compound to the aromatic compoundcan be determined by elemental analysis.

[0171] In the photochromic composition of the present invention, anotherknown photochromic compound may be used as a photochromic compound inaddition to the above molecular compound in order to adjust thedeveloped color. Any known photochromic compound such as a fulgimidecompound, spirooxazine compound or chromene compound may be used as theanother photochromic compound. A compound having color developmentcharacteristics from which a desired color is obtained is suitablyselected as the another photochromic compound according to the type ofthe molecular compound used. These photochromic compounds may besuitably mixed together to develop a suitable color.

[0172] Compounds disclosed in JP-A 2-28154(the term “JP-A” as usedherein means an “unexamined published Japanese patent application”),JP-A 62-288830, the pamphlet of WO94/22850, the pamphlet of WO96/14596and the like can be suitably used as the another photochromic compound.

[0173] The compounds newly discovered by the inventors of the presentinvention as compounds having excellent photochromism, for example, thecompounds disclosed in JP-A 2001-114775, 2001-031670, 2001-011067,2001-011066, 2000-347346, 2000-344762, 2000-344761, 2000-327676,2000-327675, 2000-256347, 2000-229976, 2000-229975, 2000-229974,2000-229973, 2000-229972, 2000-219687, 2000-219686, 2000-219685,11-322739, 11-286484, 11-279171, 10-298176, 09-218301, 09-124645,08-295690, 08-176139 and 08-157467 may be suitably used as well.

[0174] Out of these photochromic compounds, chromene-based photochromiccompounds are particularly preferred because they have higherphotochromism durability than other photochromic compounds and muchhigher color development intensity and fading speed than otherphotochromic compounds. When a chromene compound is used as the anotherphotochromic compound, it should be used in a state that it does notform a molecular compound with an aromatic compound. Therefore, achromene compound which is not used in the form of a molecular compoundis included in the another photochromic compound even though it is achromene compound represented by the above formula (1).

[0175] Examples of the chromene compound suitably used as the anotherphotochromic compound are chromene compounds having the followingstructures.

[0176] In the photochromic composition of the present invention, theamount of the another photochromic compound which may be added besidesthe above molecular compound may be suitably determined according to adesired color and not particularly limited but preferably 0.01 to 10parts by weight, particularly preferably 0.01 to 5 parts by weight basedon 100 parts by weight of the solvent for a molecular compound. When theamount of the another photochromic compound is smaller than 0.01 part byweight, the color development intensity becomes low and a satisfactorycolor control function is not obtained and when the amount is largerthan 10 parts by weight, it is difficult to dissolve it in the solventuniformly with the result that color development nonuniformity mayoccur.

[0177] Out of the photochromic compositions of the present invention, aphotochromic composition which comprises a radically polymerizablecomposition as the solvent for a molecular compound can be suitably usedas a coating for optical materials. In this case, even when the obtainedcoating layer is thin, sufficiently high color development intensity canbe obtained by increasing the concentration of the photochromiccompound. When the coating layer is thick, appropriate color developmentintensity can be obtained by reducing the amount of the molecularcompound used (that is, the amount of the chromene compound). Forinstance, when the photochromic composition is used as a coating forspectacle lenses and the thickness of the coating layer is about 10 μm,the photochromic compound is used in an amount of 5 to 0.15 parts byweight based on 100 parts by weight of the total of all the radicallypolymerizable monomers and when the thickness of the coating layer isabout 50 μm, the photochromic compound is used in an amount of 0.1 to 1part by weight to obtain preferred color development intensity.

[0178] To the photochromic composition or coating composition of thepresent invention may be added additives such as a surfactant,antioxidant, radical scavenger, ultraviolet light stabilizer,ultraviolet light absorber, release agent, discoloration preventingagent, antistatic agent, fluorescent dye, dye, pigment, perfume andplasticizer to improve the durability, color development speed, fadingspeed and moldability of the photochromic compound. When the solvent fora molecular compound is a radically polymerizable monomer, it isextremely preferred to add a polymerization initiator which will bedescribed hereinafter to cure the composition. Any known compounds maybe used as the above additives.

[0179] For example, the surfactant may be nonionic, anionic or cationicand a nonionic surfactant is preferred from the viewpoint of solubilityin polymerizable monomers. Preferred examples of the nonionic surfactantinclude sorbitan fatty acid ester, glycerin fatty acid ester,decaglycerin fatty acid ester, propylene glycol-pentaerythritol fattyacid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylenesorbitol fatty acid ester, polyoxyethylene glycerin fatty acid ester,polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether,polyoxyethylene phytosterol phytostanol, polyoxyethylenepolyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether,polyoxyethylene castor oil-cured castor oil, polyoxyethylenelanolin-lanolin alcohol-bees wax derivative, polyoxyethylenealkylamine-fatty acid amide, polyoxyethylene alkyl phenyl formaldehydecondensate and single chain polyoxyethylene alkyl ether. The abovesurfactants may be used in combination of two or more. The amount of thesurfactant is preferably 0.1 to 20 parts by weight based on 100 parts byweight of the solvent for a molecular compound.

[0180] As the antioxidant, radical scavenger, ultraviolet lightstabilizer and ultraviolet light absorber may be preferably used ahindered amine optical stabilizer, hindered phenol antioxidant,phenol-based radical scavenger, sulfur-based antioxidant,benzotriazole-based compound, benzophenone-based compound and the like.These antioxidants, radical scavengers, ultraviolet light stabilizersand ultraviolet light absorbers may be used in combination of two ormore. As for use of these nonpolymerizable compounds, a surfactant andan antioxidant, radical scavenger, ultraviolet light stabilizer orultraviolet light absorber may be used in combination. The amount of theantioxidant, radical scavenger, ultraviolet light stabilizer orultraviolet light absorber is preferably 0.001 to 20 parts by weightbased on 100 parts by weigh of the solvent for a molecular compound.

[0181] Out of the above stabilizers, a hindered amine optical stabilizeris particularly preferably used to prevent the deterioration of thephotochromic compound when the composition of the present invention isused as a coating and cured, or to improve the durability of a curedproduct thereof. The above hindered amine compounds afore-mentioned asthe amine compound having no catalytic function are used as the hinderedamine optical stabilizer. Out of these,bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and Adecastab LA-52,LA-62, LA-77 and LA-82 of Asahi Denka Kogyo K.K. are particularlypreferred because they have a great effect of preventing thedeterioration of the photochromic compound. The amount of the hinderedamine is preferably 0.001 to 20 parts by weight, particularly preferably0.1 to 10 parts by weight, the most preferably 1 to 10 parts by weightbased on 100 parts by weight of the total of all the radicallypolymerizable monomers.

[0182] The process for preparing the photochromic composition of thepresent invention is not particularly limited. Predetermined amounts ofcomponents are weighed and mixed together to obtain the photochromiccomposition of the present invention. The order of adding the componentsis not particularly limited. For instance, to prepare the abovecomposition suitable for use as a coating, all the components may beadded at the same time, or only monomer components are mixed togetherand a photochromic compound, other additives and further aphotopolymerization initiator may be added to and mixed with the abovemixture right before polymerization as will be described hereinafter.

[0183] When the photochromic composition of the present invention isobtained by mixing together the radically polymerizable monomers and theabove molecular compound, the viscosity at 25° C. thereof is preferably20 to 500 cp. When it is used as a coating for an optical article suchas a spectacle lens, the viscosity at 25° C. thereof is preferably 50 to300 cp, particularly preferably 60 to 200 cp. Within the above viscosityrange, the thickness of the coating layer can be easily adjusted to arange from 10 to 100 μm and photochromism can be developed to the full.

[0184] When the solvent of the photochromic composition of the presentinvention is a radically polymerizable monomer and the radicallypolymerizable monomer includes both an epoxy-based monomer and an aminecompound, the epoxy-based monomer and the amine compound are preferablypacked separately and mixed together before use from the viewpoint ofkeeping stability. In this case, other components may be suitablydivided and contained in the above two packages.

[0185] The method of curing the photochromic compound of the presentinvention differs according to the type of the solvent for a molecularcompound of the composition. When the solvent for a molecular compoundis a radically polymerizable monomer, a polymerization initiator isadded to cure the radically polymerizable monomer by polymerization.When the solvent for a molecular compound is a polymer compound in amolten state, the photochromic compound is cured by cooling. When thesolvent for a molecular compound is a solution of a polymer compound,the solvent of the solution is removed by vaporization.

[0186] The method of curing the photochromic compound of the presentinvention by polymerization when the solvent for a molecular compound isa radically polymerizable monomer is not particularly limited and aknown polymerization method may be employed according to the type of theradically polymerizable monomer used. Polymerization initiating means isuse of a radical polymerization initiator such as a peroxide or azocompound, exposure to radiation such as ultraviolet radiation, α-ray,β-ray or γ-ray, or both of them.

[0187] The radical polymerization initiator is not particularly limitedand any known radical polymerization initiator may be used. Typicalexamples of the thermopolymerization initiator include diacyl peroxidessuch as benzoyl peroxide, p-chlorobenzoyl peroxide, decanoyl peroxide,lauroyl peroxide and acetyl peroxide; peroxy esters such ast-butylperoxy-2-ethyl hexanoate, t-butylperoxy dicarbonate, cumylperoxyneodecanate and t-butylperoxy benzoate; percarbonates such asdiisopropylperoxy dicarbonate, di-2-ethylhexylperoxy dicarbonate anddi-sec-butyloxy carbonate; and azo compounds such as2,2′-azobisisobutyronitrile, 2,2′-azobis(4-dimethylvaleronitrile),2,2′-azobis(2-methylbutyronitrile) and1,1′-azobis(cyclohexane-1-carbonitrile).

[0188] The amount of the thermopolymerization initiator differsaccording to polymerization conditions, the type of the initiator andthe types and ratio of the polymerizable monomers and cannot be limitedunconditionally. In general, it is preferably 0.01 to 10 parts by weightbased on 100 parts by weight of the total of all the radicallypolymerizable monomers. The above thermopolymerization initiators may beused alone or in combination of two or more.

[0189] For polymerization by exposure to light such as ultravioletradiation, it is preferred to use a photopolymerization initiator suchas benzoin, benzoin methyl ether, benzoin butyl ether, benzophenol,acetophenone, 4,4′-dichlorobenzophenone, diethoxyacetophenone,2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl methyl ketal,

[0190] 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one,1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthone,bis(2,6-dimethoxybenzoyl-2,4,4-trimethyl-pentylphosphine oxide,bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,2,4,6-trimethylbenzoyldiphenyl-phosphine oxide or2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1.

[0191] The above photopolymerization initiators may be used alone or incombination of two or more. The above thermopolymerization initiatorsand the above photopolymerization initiators may be used in combination.

[0192] The photopolymerization initiator is used in an amount ofpreferably 0.001 to 10 parts by weight, more preferably 0.001 to 5 partsby weight based on 100 parts by weight of the total of all the monomers.

[0193] The particularly preferred polymerization method is that thecurable composition of the present invention which comprises the abovephotopolymerization initiator is exposed to ultraviolet radiation to becured and further heated to complete polymerization.

[0194] When polymerization is carried out by exposure to ultravioletradiation or the like, any known light source may be used. Examples ofthe light source include super high-pressure mercury lamp, high-pressuremercury lamp, low-pressure mercury lamp, xenon lamp, carbon arc,bactericidal lamp, metal halide lamp and electrodeless lamp. Theexposure time when the above light source is used may be suitablydetermined according to the type, absorption wavelength and sensitivityof the above photopolymerization initiator, the thickness of thephotochromic layer and the like. When an electron beam is used as alight source, the photochromic layer can be cured without adding aphotopolymerization initiator.

[0195] Although the photochromic composition of the present inventioncan be used alone as a photochromic material when it is cured, as thephotochromic compound is dispersed uniformly in a high concentration, itcan be particularly suitably used as a film forming composition or acoating for a substrate, for example, an optical material such as aspectacle lens, making use of the fact that a cured product having highcolor development intensity can be obtained though the thickness thereofis small.

[0196] When the photochromic composition of the present invention isused as a coating, the optical material as a substrate therefor is notparticularly limited and may be a known optical material such as aspectacle lens or window glass for houses and automobiles.

[0197] Examples of the known spectacle lens include plastic-basedspectacle lenses such as (meth)acrylic resin, polycarbonate-based resin,allyl-based resin, thiourethane-based resin, urethane-based resin andthioepoxy-based resin spectacle lenses, and glass-based spectaclelenses. The photochromic composition (as a coating) of the presentinvention may be used for all of the above spectacle lenses but it ispreferably used for plastic-based spectacle lenses because it hasexcellent adhesion to plastics. It is particularly preferably used as acoating composition for (meth)acrylic resin, polycarbonate-based resin,allyl-based resin, thiourethane-based resin, urethane-based resin andthioepoxy-based resin spectacle lenses.

[0198] When the composition of the present invention is used as acoating composition for an optical material such as a spectacle lens, itis preferred that the composition of the present invention (coating ofthe present invention) be applied to the optical material by spincoating, spray coating, dip coating, dip-spin coating or the like andcured by exposure to light or heating. More preferably, it is cured byexposure to light and then heating to complete polymerization.

[0199] When the coating composition of the present invention is to beapplied to at least one side of the above substrate and cured, asdescribed above, it can be cured optically or/and thermally by using anoptically or/and thermally radical polymerization initiator(s). From theviewpoint of the uniformity of the obtained film, curing is preferablycarried out under the condition that molecular oxygen is substantiallynonexistent (the expression “substantially nonexistent” means that theconcentration of the molecular oxygen is 10,000 ppm or less, preferably1,000 ppm or less). As for the curing method, the coating composition ofthe present invention is injected into a space formed by the substrateand a glass mold through a resin support material to be cured, or thecoating composition is polymerized after the curing atmosphere issubstituted by an inert gas. Any inert gas may be used if it is inactivewith the radical containing no oxygen. Inexpensive nitrogen or argon gashaving a high substituting effect may be used. Although theconcentration of oxygen is preferably as low as possible becausepolymerization is hardly prevented, as oxygen cannot be completelyeliminated when the atmosphere is substituted, a trace amount ofmolecular oxygen is inevitably contained. Therefore, the concentrationof oxygen in the gas is preferably 10,000 ppm or less, more preferably1,000 ppm or less because the above ill effect can be eliminated.

[0200] To coat the substrate such as a spectacle lens with the coatingcomposition of the present invention, before application of the coatingcomposition, the substrate is preferably subjected to anatmospheric-pressure plasma treatment. In general, the term“atmospheric-pressure plasma treatment” means a treatment at a higherpressure than a low-pressure plasma treatment. The pressure of thetreatment is higher than about 1 torr which is the pressure of alow-pressure plasma treatment. When a plasma treatment is carried out atthe atmospheric pressure, the surface of a resin substrate can betreated more uniformly than when the treatment is carried out at apressure other than the atmospheric pressure, for example, a vacuumplasma treatment and the structure of an apparatus can be simplifiedbecause it does not require severe air tightness.

[0201] A known gas is used as an introduction gas used for theatmospheric-pressure plasma treatment. Examples of the introduction gasis air, nitrogen, oxygen, hydrogen, carbon dioxide, carbon monoxide,sulfur dioxide, argon, helium, neon, ammonia, chlorine, nitrogenmonoxide, nitrogen dioxide and Freon-based gas such as CF₄ or C₂F₆. Airor nitrogen is preferably used from the viewpoints of handling ease andcost.

[0202] The introduction gas used for the atmospheric-pressure plasmatreatment which depends on other conditions preferably has a relativehumidity of 80. % RH or less, more preferably 40% RH or less at 24° C.The temperature for limiting the relative humidity is 24° C. but thetemperature of the introduction gas used for the atmospheric-pressureplasma is not limited. The above relative humidity of the introductiongas is a value before it is introduced into an atmospheric-pressureplasma exposure unit. By setting the relative humidity to the abovevalue, the effect of improving adhesion by the atmospheric-pressureplasma treatment becomes extremely large.

[0203] The method of producing the introduction gas having the aboverelative humidity is not particularly limited. When a gas other than airin environment is used, a gas taken out from a commercially availablegas cylinder generally has a relative humidity lower than the abovevalue. When air in environment is used, untreated air at a site wherethe atmospheric-pressure plasma exposure unit is installed or airobtained by passing the untreated air through a water absorption pipefilled with a suitable amount of a moisture absorbent such as calciumchloride or silica gel to adjust its relative humidity after it iscompressed by a compressor is used. As a matter of course, if therelative humidity of air in environment is sufficiently low, it does notneed to be let pass through the water absorption pipe.

[0204] The temperature of the introduction gas used for theatmospheric-pressure plasma treatment is not particularly limited butpreferably −5 to 100° C., more preferably 5 to 60° C.

[0205] The method of exposing plasma in the atmospheric-pressure plasmatreatment is not particularly limited but the following methods arepreferably used.

[0206] That is, (1) the resin substrate is placed on a spin coater andexposed to plasma while it is turned, (2) the resin substrate is placedbelow a fixed plasma exposure site and moved in longitudinal andtransverse directions automatically or manually so that the surface ofthe resin substrate is uniformly treated with plasma, or (3) the resinsubstrate is fixed and the plasma exposure site is moved in longitudinaland transverse directions automatically or manually so that the surfaceof the resin substrate is uniformly treated with plasma.

[0207] In the atmospheric-pressure plasma treatment, a mesh-like sheetmade from metal (including alloy) such as iron, copper, aluminum,stainless steel or SUS may be inserted between the resin substrate andthe plasma exposure site. By using the mesh-like sheet, thedeterioration by discharge or heat of the surface of the resin substrateused for the atmospheric-pressure plasma treatment can be reduced andthe atmospheric-pressure plasma treatment can be carried out efficientlywithout deteriorating the surface of the resin substrate. Further, whenthe mesh-like sheet is used, relatively high adhesion can be obtainedwithout carrying out the step of cleaning with water or an organicsolvent after the atmospheric-pressure plasma treatment which will bedescribed hereinafter.

[0208] The surface of the resin substrate may be coated with a coatingcomposition comprising a molecular compound after it is subjected to theabove atmospheric-pressure plasma treatment. Preferably, the surfacesubjected to the above atmospheric-pressure plasma treatment is cleanedwith a solvent (to be referred to as “cleaning solvent” hereinafter)before coating. This cleaning makes it easier to ensure adhesion betweenthe surface of the resin substrate and a cured product. Cleaning withthis cleaning solvent is particularly effective when the above metalmesh-like sheet is not used for the atmospheric-pressure plasmatreatment.

[0209] Examples of the cleaning solvent include water; alcohols such asmethanol, ethanol and isopropanol; ethers such as tetrahydrofurane anddioxane; organic solvents which are miscible with water in any ratio atnormal temperature, such as acetonitrile and acetone; and other organicsolvents such as 1-butyl alcohol, 2-butyl alcohol, methyl acetate, ethylacetate, diethyl ether, hexane and toluene.

[0210] These cleaning solvents may be used alone or as a mixture. It isextremely preferred from the viewpoint of an adhesion improving effectthat water be contained as one component. It is the most preferred touse water because the adhesion improving effect is obtained withextremely high reproducibility and the disposal of waste water isextremely easy.

[0211] When a mixed solvent of water and an organic solvent is used, itis particularly preferred that the organic solvent be uniformly mixedwith water. To prepare this uniform mixed solvent of water and anorganic solvent, a water-soluble organic solvent which is miscible withwater in any ratio at normal temperature is preferably used as theorganic solvent. The water-soluble organic solvent is preferablymethanol, ethanol or acetone because they are easily handled andharmless to the human body.

[0212] When the cleaning solvent is a water or a uniform mixed solventof water and an organic solvent, the mass ratio of water to the organicsolvent is preferably in the range of 100/0 to 1/99, more preferably100/0 to 15/85.

[0213] Commercially available solvents for industrial application can beused without purification as the cleaning organic solvent, and citywater, ion exchange water, distilled water, pure water and the like maybe used as water.

[0214] The temperature of the cleaning solvent, which differs accordingto the type of the resin substrate used and the types and mixing ratioof water and the organic solvent used for cleaning, is preferably −5 to100° C., more preferably 5 to 80° C.

[0215] Any known method may be used to clean the surface of the resinsubstrate with the cleaning solvent after the atmospheric-pressureplasma treatment. Preferred methods include (1) one in which the surfaceis cleaned with a cloth impregnated with the cleaning solvent, (2)supersonic cleaning, and (3) one in which the surface is cleaned with aspin coater. More specifically, in the method (1), a cloth isimpregnated with a suitable amount of the cleaning solvent and used towipe the surface of the resin substrate subjected to theatmospheric-pressure plasma treatment therewith. In the method (2), thecleaning solvent is poured into a vessel and the resin substratesubjected to the atmospheric-pressure plasma treatment is immersed inthe cleaning solvent to be cleaned ultrasonically. In the method (3),the resin substrate subjected to the atmospheric-pressure plasmatreatment is placed on a spin coater, a suitable amount of the cleaningsolvent is applied (dropped) to the surface of the resin substrate, andthen the resin substrate is cleaned while it is turned.

[0216] The number of times of carrying out the above cleaning method isnot particularly limited but preferably 0 to 10, more preferably 1 to 5from the viewpoint of productivity. Two or more of the cleaning methods(1) to (3) may be carried out on one resin substrate subjected to theatmospheric-pressure plasma treatment. When the substrate is to becleaned a plurality of times, a different cleaning solvent may be usedeach time it is cleaned.

[0217] The cleaning time, which differs according to the types, amountsand temperatures of the used resin substrate and the cleaning solventand further the cleaning method, is preferably 1 second to 30 minutes,more preferably 3 seconds to 10 minutes.

[0218] In the above methods, sufficient adhesion is obtained by applyinga curable coating composition comprising a photochromic compound to thesurface of the resin substrate subjected to the atmospheric-pressureplasma treatment after it is cleaned with a cleaning solvent as requiredand curing the curable coating composition. Since adhesion is furtherimproved by treating the resin substrate with an alkali solution beforeor after the plasma treatment of the resin substrate, the above methodcan be preferably used. The alkali solution is preferably an aqueoussolution of sodium hydroxide or an aqueous solution of potassiumhydroxide. The concentration of the hydroxide is preferably 5 to 30parts by mass. The temperature is not particularly limited and may besuitably determined in consideration of the heat resistance of thesubstrate in use. It is preferably in the range of 20 to 60° C. As forthe treatment method, the resin substrate is impregnated with the alkalisolution or ultrasonically cleaned while it is impregnated. Thetreatment time, which differs according to treating conditions, ispreferably 1 minute to 1 hour, more preferably 5 to 15 minutes. Thealkali solution may be a mixed solution of water and an alcohol solventor an alcohol solution, besides an aqueous solution. The alcohol to beused is a lower alcohol such as methanol, ethanol or isopropyl alcohol.An organic base such as 1-methyl-2-pyrrolidone may be further added asan additive in an amount of 1 to 10 parts by mass based on 100 parts bymass of the alkali solution.

[0219] The thickness of the coating layer obtained by curing inaccordance with the above method is not particularly limited butpreferably relatively large because sufficient color developmentintensity is obtained and the durability of photochromism issatisfactory even though the concentration of the photochromic compoundis low. However, as the thickness of the coating layer becomes larger,initial yellowness increases. Therefore, the thickness of the coatinglayer is preferably 10 to 100 μm, more preferably 20 to 50 μm. Thiscoating thickness can be easily obtained by adjusting the viscosity at25° C. of the curable composition to preferably 20 to 500 cp, morepreferably 50 to 300 cp, much more preferably 60 to 200 cp.Conventionally known coating compositions (which do not contain a silylmonomer, photochromic material, etc.) contain a solvent to obtain auniform film and accordingly has a viscosity of 5 cp or less, and thethickness of a coating layer obtained therefrom is several μm or less.

[0220] When the composition of the present invention is used as acoating composition for a spectacle lens, the ratio of components of thecomposition, particularly the radically polymerizable monomer ispreferably adjusted to ensure that the refractive index of a curedproduct thereof becomes almost equal to that of the spectacle lens.Generally speaking, the refractive index is adjusted to about 1.48 to1.75.

[0221] When the composition of the present invention comprises the abovesilyl monomer and/or isocyanate monomer and the amine compound and isused as a coating composition for an optical material such as aspectacle lens, particularly a plastic-based spectacle lens, it exhibitsextremely high adhesion to the optical material.

[0222] Although the thus coated optical material can be directly used asa photochromic optical material, it is more preferably coated with ahard coat material. When it is coated with a hard coat material, thescratching resistance of the photochromic optical material can beimproved.

[0223] Any known hard coat material can be used, as exemplified by silancoupling agents, hard coatings essentially composed of a sol of an oxideof silicon, zirconium, antimony or aluminum, and hard coatingsessentially composed of an organic polymer. The curable composition ofthe present invention has high adhesion to a hard coat whichconventionally known compositions have poor adhesion to and aretherefore difficult to be used with and which is cured by a condensationmethod and is therefore extremely useful. Further, processing and asecondary treatment such as antireflection treatment and antistatictreatment may be made on the surface of a single cured product of thecurable composition of the present invention, the cured surface of acoating material for an optical material or the hard coated surface ofthe coating layer by depositing a thin film of a metal oxide such asSiO₂, TiO₂ or ZrO₂ or applying an organic polymer to form a thin film.

[0224] Since the molecular compound of the present invention shows thesame excellent photochromism as the chromene compound constituting themolecular compound, it can be used as a recording material such as arecording material substituting a silver salt photosensitive material,copy material, printing photosensitive material, recording material forcathode ray tubes, laser photosensitive material or holographyphotosensitive material.

[0225] The molecular compound of the present invention is soluble ingeneral organic solvents such as toluene, chloroform andtetrahydrofuran, monomers and molten polymers and is quickly dissolved.For instance, the dissolution time of the molecular compound when it isdissolved in a high concentration is much shorter than the dissolutiontime of only a chromene compound which is not in the form of a molecularcompound. A solution or dispersion in a polymer solid matrix of themolecular compound shows an excellent reversible photochromic functionthat it is almost achromatic and transparent when it is not exposed tolight, develops a color quickly upon exposure to sunlight or ultravioletradiation and returns to its original breached state quickly when lightis shut off. Since a photochromic compound can be uniformly dispersed ina polymer matrix in a high concentration by dissolving the molecularcompound of the present invention in a monomer or a molten polymer toprepare the photochromic composition of the present invention and curingthe composition, even when the thickness of the polymer matrix layer issmall, high color development intensity can be obtained. Therefore,various methods of providing photochromism to materials can be employed.For instance, in addition to the above coating, a method in which apolymer film comprising a photochromic compound uniformly dispersed in ahigh concentration is obtained by using the molecular compound of thepresent invention and sandwiched between lenses; a method in which thesurface of a lens is covered with the polymer film and further with acurable substance; a method in which the molecular compound of thepresent invention is dissolved in silicone oil, the resulting solutionis impregnated into the surface of a lens by heating at 150 to 200° C.for 10 to 60 minutes and the surface of the lens is coated with acurable substance are employed to obtain a photochromic lens havinguniform light control performance.

EXAMPLES

[0226] The following examples are provided for the purpose of furtherillustrating the present invention but are in no way to be taken aslimiting.

Production Example 1

[0227] 10 g (21.6 mmol) of the following hydroxyl compound and 10.1 g(35 mmol) of the following propargyl alcohol derivative were dissolvedin 500 ml of toluene, and further 0.5 g of p-toluenesulfonic acid wasadded to reflux the resulting solution for 1 hour. Thereafter, theobtained chromene compound (C) shown below was purified by silica gelcolumn chromatography to produce 7.2 g of a product having an HPLCpurity of 99% (yield of 45%).

Production Example 2

[0228] 10 g (43 mmol) of the following naphthalene derivative and 15 g(47 mmol) of the following propargyl alcohol derivative were dissolvedin 500 ml of toluene, and further 0.5 g of p-toluenesulfonic acid wasadded to reflux the resulting solution for 1 hour. Thereafter, theobtained chromene compound (D) shown below was purified by silica gelcolumn chromatography to produce 5.6 g of a product having an HPLCpurity of 99% (yield of 25%).

Example 1

[0229] 10 g (21.6 mmol) of the following hydroxyl compound and 10.1 g(35 mmol) of the following propargyl alcohol derivative were dissolvedin 500 ml of toluene, and further 0.5 g of p-toluenesulfonic acid wasadded to reflux the resulting solution for 1 hour.

[0230] The toluene solution obtained after the reaction mixture waswashed with water to remove p-toluenesulfonic acid solvent wasconcentrated by distilling off toluene under reduced pressure. When thesolution was concentrated until the amount of the remaining solution ofthe reaction mixture became about 100 ml and stirred at room temperaturefor 24 hours, an ocher crystal was precipitated. When the obtainedcrystal was filtered, 8 g of an ocher powdery crystal was obtained. Thecrystal was dissolved in 80 ml of toluene (10 times the volume of theobtained crystal) by heating and stirred at room temperature for 24hours to be recrystallized and filtered. The same operation was repeated5 times to produce about 1 g of a yellow powdery crystal. When thecollected product was dried at 80° C. under reduced pressure until aweight reduction was not seen, 0.5 g of a yellow powdery crystal wasobtained.

[0231] When elemental analysis was made on the crystal, the crystalcontained 85.01% of C, 5.70% of H, 1.59% of N and 7.74% of O which didnot agree with the calculated values of the chromene compound (C) alonebut agreed very closely with the calculated values of a molecularcompound of the chromene compound (C) and toluene in a ratio of 1:1(84.97% of C, 5.68% of H, 1.68% of N and 7.67% of O). When the protonnuclear magnetic resonance spectrum of the crystal was measured, peaksderived from the chromene compound (C), that is, a peak corresponding to25H at δ of 5.0 to 8.6 ppm based on an aromatic proton and alkeneproton, a peak corresponding to 6H at δ of 4.0 ppm and 3.5 ppm based ona methoxy group, a peak corresponding to 4H at δ of 3.8 ppm and 3.1 ppmbased on a morpholino group; and a peak corresponding to 3H at δ of 2.36ppm based on a methyl group of toluene, and a peak corresponding to 5Hat δ of 7.2 to 7.3 ppm based on the aromatic proton of toluene wereconfirmed. It was found from comparison of integral values that themolar ratio of the chromene compound (C) to toluene was 1:1. The NMRchart of the molecular compound is shown in FIG. 1. Further, when themelting point of the above crystal was measured with the EX-PAR6000differential thermal analyzer of Seiko Instruments Inc., no heatabsorption peak was observed except 162° C. which was the melting pointof the crystal and no heat absorption peak was observed even at 110° C.which was the boiling point of toluene. The chart of differentialthermal analysis is shown in FIG. 2. It was confirmed from the aboveresults that toluene as a solvent did not simply adhere to the chromenecompound (C) in the above crystal but the above crystal was themolecular compound of the chromene compound and toluene.

[0232] In order to investigate the dissolution speed of the abovemolecular compound in a monomer, 5 parts by weight of the molecularcompound was added to a monomer solution which was a mixture of 70 partsby weight of tetraethylene glycol dimethacrylate, 15 parts by weight oftriethylene glycol dimethacrylate, 10 parts by weight of glycidylmethacrylate and 5 parts by weight of 2-hydroethyl methacrylate at 25°C. and fully stirred to measure the time elapsed until it was completelydissolved by the eye. Although the amount of the molecular compound waslarge at 5 parts by weight, the time required for complete dissolutionwas only 6 minutes, which means that it dissolved quickly.

Example 2

[0233] 1 g of the chromene compound (D) after purification obtained inProduction Example 2 was added to 5 ml of toluene, dissolved by heating,naturally cooled to room temperature, and stirred overnight at roomtemperature to precipitate a crystal. The precipitated crystal powderwas collected by filtration and the collected product was dried at 80°C. under reduced pressure until a weight reduction was not seen toproduce 0.46 g of a yellow powdery crystal.

[0234] When elemental analytical was made on the crystal, the crystalcontained 78.20% of C, 6.45% of H, 3.11% of F, 4.66% of N and 7.88% of Owhich did not agree with the calculated value of the chromene compound(D) alone but agreed very closely with the calculated values of a 1:1molecular compound of the chromene compound (D) and toluene (78.15% ofC, 6.39% of H, 4.56% of N and 7.81% of O). When the proton nuclearmagnetic resonance spectrum of the crystal was measured, peaks derivedfrom the chromene compound (D), that is, a peak corresponding to 16H atδ of 3.0 to 3.1 ppm and 3.7 to 3.8 ppm based on a morpholino group and apeak corresponding to 15H at δ of 6.0 to 8.4 ppm based on an aromaticproton and alkene proton; and a peak corresponding to 3H at δ of 2.36ppm based on the methyl group of toluene and a peak corresponding to 5Hat δ of 7.2 to 7.3 ppm based on the aromatic proton of toluene wereconfirmed. It was found by comparison of integrated values that themolar ratio of the chromene compound (D) to toluene was 1:1. The meltingpoint and the dissolution speed were measured in the same manner was inExample 1. The melting point and the dissolution speed are shown inTable 1. TABLE 1 Constituent molecules of molecular compound propertiesof molecular compound aromatic compound melting point amount/dissolutionspeed No. Chromene compound (molecular weight) (° C.) (parts byweight)/(hour) Ex.1

Toluene (92) 162 5/0.1 Ex.2

Toluene (92) 113 5/0.05

Comparative Example 1

[0235] 1 g of the purified chromene compound (C) obtained in ProductionExample 1 was dissolved in 20 ml of ethyl acetate by heating and stirredovernight at room temperature. The precipitated powder was filtered anddried at 80° C. under reduced pressure until a weight reduction was notseen to produce 0.77 g of a light green crystal. The elemental analysisvalues of the crystal were 84.20% of C, 5.33% of H, 1.99% of N and 8.68%of O which agreed very closely with the calculated values of thechromene compound (C)(84.19% of C, 5.30% of H, 1.89% of N and 8.63% ofO). When the proton nuclear magnetic resonance spectrum of the crystalwas measured, only a peak derived from the chromene compound (C) shownin Example 1 was confirmed. It could be confirmed from the above resultsthat the crystal was the chromene compound (C) and that it did not forma molecular compound with ethyl acetate unlike Example 1. The meltingpoint and dissolution speed of the product were measured in the samemanner as in Example 1 except that the amount of the product to be addedto the monomer solution to obtain its dissolution speed was changed to0.5 part by weight. The results are shown in Table 2. The chart of thedifferential thermal analysis of the product is shown in FIG. 3 forcomparison with the molecular compound of Example 1.

Comparative Example 2

[0236] 1 g of the purified chromene compound (D) obtained in ProductionExample 2 was dissolved in 10 ml of acetonitrile by heating and stirredovernight at room temperature. The precipitated powder was filtered anddried at 80° C. under reduced pressure until a weight reduction was notseen to produce 0.89 g of an orange crystal.

[0237] The elemental analysis values of the crystal were 75.89% of C,5.89% of H, 3.76% of F, 5.44% of N and 9.22% of O which agreed veryclosely with the calculated values of the chromene compound (D)(75.84%of C, 5.98% of H, 3.64% of F, 5.36% of N and 9.18% of O). When theproton nuclear magnetic resonance spectrum of the crystal was measured,only a peak derived from the chromene compound (D) shown in Example 2was confirmed.

[0238] It could be confirmed from the above results that the crystal wasthe chromene compound (D) and that it did not form a molecular compoundwith acetonitrile unlike Example 2.

[0239] The melting point and dissolution speed of the product weremeasured in the same manner as in Example 1 except that the amount ofthe product to be added to the monomer solution to obtain itsdissolution speed was changed to 0.5 part by weight. The results areshown in Table 2. TABLE 2 properties of chromene compound melting pointamount/dissolution speed No. Chromene compound (° C.) (parts byweight)/(hour) C.Ex.1

273 0.5/84 C.Ex.2

185 0.5/2

[0240] When Table 1 and Table 2 are compared with each other, Exampleshave a lower melting point than Comparative Examples and 10 times ormore faster dissolution speed than Comparative Examples although theamount is 10 times larger.

Example 3

[0241] 0.02 part by weight of 2,4,6-trimethylbenzoyldiphenyl phosphineoxide as a photopolymerization initiator and 0.5 part by weight oft-butylperoxy-2-ethyl hexanoate as a thermopolymerization initiator wereadded to 100 parts by weight of the monomer solution containing themolecular compound used for the measurement of dissolution speed inExample 1, fully mixed together and deaerated under reduced pressure.This mixed solution was poured into a mold formed using a glass plateand a gasket made from ethylene-vinyl acetate copolymer and exposed toan activation energy ray from a distance of 25 cm on both sides for 1minute using a 1.5 kw metal halide lamp (with a heat ray cut filter) tocarry out photopolymerization. Thereafter, the molded product was curedat 110° C. in a polymerization furnace for 1 hour and separated from aglass mold to obtain a 0.1 mm-thick photochromic polymer.

[0242] The obtained 0.1 mm-thick photochromic polymer was exposed toelectron beams having an intensity on the surface of the polymer of 2.4mW/cm² at 365 nm and 24 μW/cm² at 245 nm using the L-2480 SHL-100 xenonlamp (300 W) of Hamamatsu Photonics Co., Ltd. through an aeromass filter(of Corning Co., Ltd.) at 20° C.±1° C. for 120 seconds to develop acolor and measure its photochromism. The photochromism was expressed bythe following.

[0243] (1) maximum absorption wavelength (λmax): λmax after the colordevelopment of this polymer was obtained by the spectrophotometer(MCPD1000 instantaneous multi-channel photodetector) of Otsuka DenshiKogyo Co., Ltd.

[0244] (2) color development intensity {ε(120)−ε(0)}: the differencebetween absorbance ε(120) after 120 seconds of exposure at the abovemaximum absorption wavelength and ε(0). It can be said that as thisvalue becomes larger, photochromism is better. A photochromic polymerpreferably has a color development intensity of 1.0 or more when it isused as an ordinary light control spectacle material.

[0245] (3) Fading speed [τ1/2 (min.)]: the time required for theabsorbance of this polymer to be reduced to half of {ε(120)−ε(0)} after120 seconds of exposure. It can be said that as this time becomesshorter, photochromism is better.

[0246] The results are shown in Table 3.

Example 4

[0247] The procedure of Example 3 was repeated except that 100 parts byweight of the monomer solution (photochromic monomer) containing themolecular compound used for the measurement of dissolution speed inExample 2 was used as the photochromic monomer. The results are shown inTable 3. TABLE 3 amount of color Molecular molecular development fadingcompound compound λmax intensity speed No. No. (parts by weight) (nm)ε(120)-ε(0) τ½ (min.) Ex. 3 Ex. 1 5 610 1.15 2.1 Ex. 4 Ex. 2 5 472 1.082.8

Comparative Example 3

[0248] The procedure of Example 3 was repeated except that thephotochromic monomer prepared in Comparative Example 1 was used as thephotochromic monomer. The results are shown in Table 4.

Comparative Example 4

[0249] The procedure of Example 3 was repeated except that thephotochromic monomer prepared in Comparative Example 2 was used as thephotochromic monomer. The results are shown in Table 4. TABLE 4 amountof color fading Chromene chromene development speed compound compoundλmax intensity τ½ No. No. (parts by weight) (nm) ε(120)-ε(0) (min.) C.Ex. 3 C. Ex. 1 0.5 610 0.42 1.8 C. Ex. 4 C. Ex. 2 0.5 472 0.33 2.5

[0250] As understood from Table 3 and Table 4, since the content of thechromene compound in the photochromic polymer was about 10 times higherin Examples than in Comparative Examples, the polymers of Examplesshowed excellent photochromism with higher color development intensityeven when they were as thin as 0.1 mm.

Example 5

[0251] 0.02 part by weight of 2,4,6-trimethylbenzoyldiphenylphosphineoxide as a photopolymerization initiator and 0.5 part by weight oft-butylperoxy-2-ethyl hexanoate as a thermopolymerization initiator wereadded to 100 parts by weight of the photochromic monomer prepared inExample 1 as a photochromic monomer, fully mixed together and deaeratedunder reduced pressure. This mixed solution was poured into a moldformed using a glass plate, an ADC resin board (thickness of 2.0 mm) anda gasket made from ethylene-vinyl acetate copolymer and exposed to anactivation energy ray from a distance of 25 cm on both sides for 1minute using a 1.5 kw metal halide lamp (with a heat ray cut filter) tocarry out photopolymerization. Thereafter, the molded product was curedat 110° C. in a polymerization furnace for 1 hour and separated from aglass mold to obtain an ADC resin having a 0.1 mm-thick photochromicpolymer on one side. When the photochromism of this optical material wasevaluated in the same manner as in Example 3, it was almost equivalentto that of Example 3.

Example 6

[0252] The entire convex surface of a 2 mm-thick plastic lens (resinsubstrate: CR39) was subjected to an atmospheric-pressure plasmatreatment for 90 seconds using an atmospheric-pressure plasma exposureunit (ST-7000 of Keyence Co., Ltd.). The distance between the exposuresite and the lens was about 10 mm and a SUS mesh sheet was insertedbetween the exposure site and the lens. Nitrogen obtained from acommercially available nitrogen cylinder was used as the introductiongas for the plasma treatment. When the relative humidity of air suppliedfrom the nitrogen cylinder was measured, it was 14% at 24° C.(temperature/humidity meter of Iuchi Seieido Co., Ltd.: TR-72S).

[0253] Subsequently, 5 parts by weight of the molecular compound (C),0.4 part by weight of CGI184 as a photopolymerization initiator and 0.1part by weight of CGI403 (as for abbreviations, refer to Example 7) wereadded to 100 parts by weight of polymerizable monomers consisting of 50parts by weight of polyethylene glycol diacrylate having an averagemolecular weight of 532 and 50 parts by weight of glycidyl methacrylate,and stirred and mixed together at room temperature for 12 hours.

[0254] About 2 g of the mixed solution obtained by the above method wasapplied to the surface of a plastic lens (CR39) subjected to the aboveplasma treatment with the 1H-DX2 spin coater of MIKASA Co., Ltd. at arevolution speed of 60 rpm for 40 seconds, 500 rpm for 2 seconds and1,000 rpm for 2 seconds. This lens having the coated surface was exposedto light using a metal halide lamp having an output of 120 mW/cm² in annitrogen gas atmosphere for 2 minutes to cure the coating film.Thereafter, the lens was further heated at 110° C. for 2 hours. Thecomposition of the used compound is shown in Table 5.

[0255] Using the obtained lens having a photochromic coating layer as asample, the maximum absorption wavelength, color development intensityand fading speed of the photochromic coating layer, adhesion between thephotochromic coating layer and the lens and the thickness of the coatinglayer were measured by the following methods.

[0256] The maximum absorption wavelength (1), color developmentintensity (2) and fading speed (3) were evaluated in the same manner asin Example 3.

[0257] (4) developed color: The developed color is evaluated outdoors bythe eye.

[0258] (5) uniformity of photochromic coating layer: It is evaluated bythe eye whether the precipitated crystal is existent in the photochromiccoating layer after the end of polymerization. When no crystalprecipitation is seen in the molecular compound or the photochromiccompound and the photochromic coating layer is amorphous, it is judgedas ◯ and when crystal precipitation is apparent and the photochromiccoating layer looks cloudy, it is evaluated as X.

[0259] (6) color development nonuniformity: Color is developed from thelens sample with sunlight outdoors and it is evaluated whether colordevelopment is uniform or not by the eye. When color development isuniform, it is judged as ◯ and when color development is not uniform, itis judged as X.

[0260] (7) adhesion between lens and photochromic coating layer(adhesion 1): One hundred 1 mm×1 mm squares are formed by cutting thesurface of the coating layer of the lens having a photochromic coatinglayer by a sharp cutting knife. Then, commercially available Cellotapeis affixed to the surface and stripped off quickly to check the strippedstate of the coating layer (coating film) by the eye. When all thesquares still adhere to the surface, adhesion is judged as ◯, when someof the squares are removed, adhesion is judged as Δ, and when all thesquares are removed, adhesion is judged as X.

[0261] (8) thickness of photochromic layer: This is measured using thethin film measuring instrument of Filmetrics Co., Ltd.

[0262] Subsequently, the lens having a photochromic coating layerobtained by the above process is cleaned with acetone, dried with aircompletely to obtain a clear state, immersed in a 10% NaOH aqueoussolution for 10 minutes, rinsed fully with water and dried with airagain. This lens is immersed in the TS56H hard coat solution(condensation hard coat material of Tokuyama Corporation), pulled up ata rate of 30 mm/min, pre-dried at 60° C. for 15 minuets and cured byheating at 120° C. for 3 hours to obtain a sample having a hard coatlayer. Using this sample, adhesion between the photochromic coatinglayer and the hard coat material is evaluated.

[0263] (9) adhesion between photochromic coating layer and hard coatmaterial (adhesion 2): One hundred mm² squares are formed on the surface(covered with a hard coat layer) on a photochromic layer side of thehard coated lens by a sharp cutting knife and commercially availableCellotape is affixed to the surface and stripped off quickly to checkthe stripped states of the hard coat layer and the photochromic coatinglayer by the eye. When all the squares still adhere to the surface,adhesion is judged as ◯, when some of the squares are removed, adhesionis judged as Δ, and when all the squares are removed, adhesion is judgedas X. The results are shown in Table 7.

Examples 7 to 15

[0264] The procedure of Example 6 was repeated to obtain a lens having aphotochromic coating layer except that the types and amounts of theradically polymerizable monomer, amine compound, molecular compound,photochromic compound (chromene compound, spirooxazine compound),polymerization initiator and stabilizer used to prepare a coating andthe type of the resin substrate were changed as shown in Table 5, andthe lens was evaluated in the same manner as in Example 6. The resultsare shown in Table 7.

[0265] In Table 5, the used compounds are expressed by abbreviations.Each abbreviation represents the following compound. As for the otherradically polymerizable monomers, the L-scale Rockwell hardness of acured product obtained by cast homopolymerizing each compound (monomer)(polymerized by heating from 30° C. to 90° C. over 20 hours and furtherpolymerized by heating at 120° C. for 2 hours) is given as “homo-HL”within parentheses. As for the method of measuring the hardness, thehardness is measured with an Akashi Rockwell hardness meter (type:AR-10) after a cured product is kept in a chamber maintained at 25° C.for 1 day. Glycidyl methacrylate is an epoxy-based monomer.

[0266] (1) Radically Polymerizable Monomers

[0267] TMPT: trimethylolpropane trimethacrylate (homo-HL=122)

[0268] DPEHA: dipentaerythritol hexaacrylate (homo-HL=100)

[0269] U6A: urethane oligomer hexaacrylate (homo-HL=100) (Shin-NakamuraKagakusha: U-6HA)

[0270] EB6A: polyester oligomer hexaacrylate (homo-HL=100) (Daicel UCB:EB1830)

[0271] GMA: glycidyl methacrylate (homo-HL=80)

[0272] BPE: 2,2-bis(4-methacryloyloxyethoxyphenyl)propane (homo-HL=110)

[0273] DVB: divinylbenzene (homo-HL=110)

[0274] BSA: (homo-HL=105)

[0275] BBA: (homo-HL=80)=

[0276] BZMA: benzyl methacrylate (homo-HL=80)

[0277] 9GDA: polyethylene glycol diacrylate having an average molecularweight of 532 (homo-HL<20)

[0278] MePEGMA (475): methyl ether polyethylene glycol methacrylatehaving an average molecular weight of 1,000 (homo-HL<20)

[0279] BPE oligomer: 2,2-bis(4-acryloyloxypolyethylene glycolphenyl)propane having an average molecular weight of 776 (homo-HL<40)silyl monomer

[0280] TMSiMA: γ-methacryloyloxypropyltrimethoxysilane

[0281] DMSiMA: γ-methacryloyloxypropylmethyldimethoxysilane isocyanatemonomer

[0282] MOI: 2-isocyanatoethoxy methacrylate

[0283] (2) Amine Compounds

[0284] NMDEA: N-methyldiethanolamine

[0285] DMEMA: N,N-dimethylaminoethyl methacrylate

[0286] (3) Molecular Compounds

[0287] molecular compound (C): molecular compound of chromene (C) andtoluene obtained in Example 1

[0288] molecular compound (D): molecular compound of chromene (D) andtoluene obtained in Example 2

[0289] (4) Photochromic Compounds

[0290] chromene (A)

[0291] chromene (B)

[0292] chromene (C): chromene compound obtained in Production Example 1

[0293] chromene (D): chromene compound obtained in Production Example 2

[0294] chromene (E)

[0295] chromene (F)

[0296] chromene (G)

[0297] spirooxazine (A)

[0298] spirooxazine (B)

[0299] (5) Polymerization Initiators

[0300] CGI184: 1-hydroxycyclohexylphenyl ketone

[0301] CGI403: bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphineoxide

[0302] Perbutyl O: t-butylperoxy-2-ethyl hexanoate

[0303] (6) Stabilizers

[0304] LS765: bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate

[0305] (7) Optical Materials

[0306] CR39: (allyl resin plastic lens; refractive index=1.50) MR(thiourethane-based resin plastic lens; refractive index=1.60)

[0307] TE (thioepoxy-based resin plastic lens; refractive index=1.71)

[0308] SPL (methacrylic resin plastic lens; refractive index=1.54)

Comparative Examples 3 and 4

[0309] A lens having a photochromic coating layer was obtained in thesame manner as in Example 6 except that a radically polymerizablemonomer, amine compound, photochromic compound, polymerizationinitiator, stabilizer and resin substrate were changed as shown in Table6 and that a molecular compound was not used.

[0310] Since the molecular compound was not used, they were notdissolved in high concentrations but cured as a slurry solution.

[0311] The obtained lens was evaluated by the above evaluation methodsand the obtained results are shown in Table 8. TABLE 5 silyl monomer/amine compound polymerization Ex. Radically polymerizable monomerisocyanate monomer (parts by initiator No. (parts by weight) (parts byweight) weight) (parts by weight)  6 9GDA/GMA — — CGI184/CGI403 50/50 0.4/0.1  7 9GDA/GMA — — CGI184/CGI403 50/50  0.4/0.1  8 9GDA/GMA — —CGI184/CGI403 50/50  0.4/0.1  9 9GDA/DVB/GMA — — CGI184/CGI403 40/40/20 0.4/0.1 10 TMPT/BPE/U6A/9GDA/GMA TMSiMA 1 NMDEA CGI184/Perbutyl O20/39/10/20/10 0.1  0.5/0.1 11 DPEHA/BPEoligomer/EB6A/9GA/GMA DMSiMA 3NMDEA 3 CGI184/CGI403 20/37/10/20/10   1/0.1 12 BBA/BPE/TMPT/MePEGMA/GMAMOI 2 DMDEA 2 CGI403/Perbutyl O 35/35/10/8/10 0.05/1 13BSA/BzMA/TMPT/9GDA/GMA TMSiMA 3 NMDEA 5 CGI403/Perbutyl O 35/35/10/7/100.01/1 14 BPEoligomer/TMPT/EB6A/9GDA/GMA TMSiMA 7 NMDEA 3 CGI184/CGI40335/15/15/15/10  0.4/0.1 15 BPEoligomer/TMPT/EB6A/9GDA/GMA TMSiMA 7 NMDEA3 CGI184/CGI403 35/15/15/15/10  0.4/0.1 Ex. Stabilizer optical molecularcompound chromene compound spirooxazine compound No. (parts by weight)material (parts by weight) (parts by weight) (parts by weight)  6 — CR39(C) — —  5  7 — CR39 (D) — —  5  8 — MR (C) — — 10  9 — MR (C) — — 15 10LS765 5 TE (C) — —  5 11 LS765 5 SPL (D) (G) 2 —  3 12 LS765 5 SPL(C)/(D) (A) — 5/3 0.5 13 LS765 5 CR39 (C)/(D) (B)/(E)/(F) — 5/20.5/0.5/0.3 14 LS765 5 MR (C)/(D) (B) (A)/(B)   3/0.9 0.6 0.3/0.3 15LS765 5 MR (C)/(D) (B) (A)/(B) 1.6/2.4 0.2 0.2/0.2

[0312] TABLE 6 Radically silyl monomer/ polymerization C. Ex.polymerizable monomer isocyanate monomer amine compound initiator No.(parts by weight) (parts by weight) (parts by weight) (parts by weight)3 9GDA/GMA — — CGI184/CGI403 50/50 0.4/0.1 4 9GDA/GMA — — CGI184/CGI40350/50 0.4/0.1 molecular chromene spirooxazine C. Ex. Stabilizer opticalcompound compound compound No. (parts by weight) material (parts byweight) (parts by weight) (parts by weight) 3 — CR39 — (C) 5 — 4 — CR39— (D) 5 —

[0313] TABLE 7 Color fading color film Ex. λmax development speeddeveloped development adhesion 1 thickness adhesion 2 No. (nm) intensity(min) color uniformity nonuniformity (substrate) (μm) (hard coat) 6 6100.66 1.3 Blue ◯ ◯ ◯ 15 ◯ 7 470 0.60 1.9 Orange ◯ ◯ ◯ 15 ◯ 8 610 0.81 1.4Blue ◯ ◯ ◯ 18 ◯ 9 610 0.93 1.8 Blue ◯ ◯ Δ 20 Δ 10 610 0.82 1.4 Blue ◯ ◯◯ 32 ◯ 11 470 0.77 1.9 Amber ◯ ◯ ◯ 40 ◯ 598 0.67 1.3 12 476 0.65 1.8Gray ◯ ◯ ◯ 28 ◯ 610 0.72 1.4 13 470 0.62 1.9 Gray ◯ ◯ ◯ 25 ◯ 610 0.701.4 14 472 0.80 1.9 Gray ◯ ◯ ◯ 40 ◯ 610 0.83 1.3 15 470 0.90 1.9 Brown ◯◯ ◯ 41 ◯ 610 0.78 1.3

[0314] TABLE 8 Color fading color film C. Ex. λmax development speeddeveloped development adhesion 1 thickness adhesion 2 No. (nm) intensity(min) color uniformity nonuniformity (substrate) (μm) (hard coat) 3 6100.2 3.0 Blue X X X 17 X 4 470 0.11 3.5 Orange X X X 14 X

[0315] The curable composition and coating composition comprising amolecular compound of the present invention have extremely highsolubility in monomers and the like and are easily dispersed in apolymer matrix uniformly in a high concentration, making use of thisproperty. Therefore, especially for applications that require smallthickness, for example, when a thin film of a photochromic polymer isformed and used to control light, the content of the photochromiccompound can be increased, thereby making it possible to obtain a thinfilm having excellent photochromism.

1. A photochromic composition obtained by mixing together (1) 100 partsby weight of a radically polymerizable monomer or a polymer compound and(2) 0.01 to 20 parts by weight of a molecular compound of a chromenecompound and an aromatic compound.
 2. The composition of claim 1 whichfurther comprises 10 parts or less by weight of a photochromic compound.3. The composition of claim 1, wherein the molecular compound is amolecular compound of a chromene compound represented by the followingformula (1):

wherein R¹ and R² are each a substituted or nonsubstituted aryl group,or a substituted or nonsubstituted aromatic heterocyclic group, and thedivalent group represented by the following formula (2) is a divalentcondensed polycyclic organic group which has a benzene ring condensed tothe 2H-pyran ring in the above formula (1) and may have a substituent,

and an aromatic compound having a molecular weight of 70 to
 150. 4. Thecomposition of claim 1 which is obtained by mixing together 100 parts byweight of a radically polymerizable monomer and 0.01 to 20 parts byweight of the above molecular compound and further comprises 0.001 to 10parts by weight of a photopolymerization initiator.
 5. A coatingcomposition obtained by mixing together (1) 100 parts by weight of aradically polymerizable monomer, (2) 1 to 30 parts by weight of amolecular compound of a chromene compound and an aromatic compound, or acombination of this molecular compound and a photochromic compound, and(3) 0.01 to 10 parts by weight of a photopolymerization initiator, thenumber of parts by weight of the component being smaller than the numberof parts by weight of the component (2).
 6. The coating composition ofclaim 5, wherein the amount of the photochromic compound is 10 parts orless by weight based on 1 to 30 parts by weight of the total of themolecular compound and the photochromic compound.
 7. The coatingcomposition of claim 5, wherein the molecular compound is a molecularcompound of a chromene compound represented by the following formula(1):

wherein R¹ and R² are each a substituted or nonsubstituted aryl group,or a substituted or nonsubstituted aromatic heterocyclic group, and thedivalent group represented by the following formula (2) is a divalentcondensed polycyclic organic group which has a benzene ring condensed tothe 2H-pyran ring in the above formula (1) and may have a substituent,

and an aromatic compound having a molecular weight of 70 to
 150. 8. Aphotochromic optical material which is a cured product of thecomposition of any one of claims 1 to
 4. 9. A process for producing aphotochromic optical material, comprising curing the composition of anyone of claims 1 to
 4. 10. A photochromic optical material comprising asubstrate and a cured coating film of the coating composition of any oneof claims 5 to 7 on at least one side of the substrate.
 11. Thephotochromic optical material of claim 10 which is a photochromic lenscomprising a lens as the substrate.
 12. A process for producing aphotochromic optical material, which comprises applying the coatingcomposition of any one of claims 5 to 7 to at least one side of asubstrate and curing the coating film by light or both light and heat.13. The process of claim 12, wherein curing is carried out in theabsence of molecular oxygen.
 14. A molecular compound of a chromenecompound represented by the following formula (1):

wherein R¹ and R² are each a substituted or nonsubstituted aryl group,or a substituted or nonsubstituted aromatic heterocyclic group, and thedivalent group represented by the following formula (2) is a divalentcondensed polycyclic organic group which has a benzene ring condensed tothe 2H-pyran ring in the above formula (1) and may have a substituent,

and an aromatic compound having a molecular weight of 70 to
 150. 15. Aprocess for producing a molecular compound, comprising contacting anaromatic compound having a molecular weight of 70 to 150 to a chromenecompound represented by the above formula (1) in a solution toprecipitate a molecular compound of the chromene compound and thearomatic compound as a crystal.